4.Suatu fungsi didefinisikan dengan rumus f(x) = ax + b,

Berikut ini adalah pertanyaan dari amandaputriokt84 pada mata pelajaran Matematika untuk jenjang Sekolah Menengah Pertama

4.Suatu fungsi didefinisikan dengan rumus f(x) = ax + b, jika diketahui f(3)- 15 dan f(5)-20 Tentukan: a. Nilai a dan b b. Rumus fungsinya c. Gambar grafik fungsinya d. f(-2)​

Jawaban dan Penjelasan

Berikut ini adalah pilihan jawaban terbaik dari pertanyaan diatas.

Jawaban:

Diketahui begin mathsize 14px style f open parentheses 3 close parentheses equals 15 end style dan begin itu jawaban nya ada pada gambar ya kalau sala tolong di maaf kanmathsize 14px style f open parentheses 5 close parentheses equals 20 end style, sehingga:

begin mathsize 14px style f left parenthesis x right parenthesis equals a x plus b f open parentheses 3 close parentheses equals 15 space rightwards arrow 3 a plus b equals 15 space.... open parentheses 1 close parentheses f open parentheses 5 close parentheses equals 20 space rightwards arrow 5 a plus b equals 20 space.... open parentheses 2 close parentheses end style

Eliminasi persamaan (1) dan (2).

begin mathsize 14px style table row cell 3 a plus b equals 15 end cell row cell 5 a plus b equals 20 end cell row cell negative 2 a equals negative 5 end cell row cell a equals 5 over 2 end cell end table minus end style

Subtitusi nilai begin mathsize 14px style a end style ke persamaan (1) atau (2)

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell 3 a plus b end cell equals 15 row cell 3 times open parentheses 5 over 2 close parentheses plus b end cell equals 15 row cell 15 over 2 plus b end cell equals 15 row b equals cell 15 minus 15 over 2 end cell row b equals cell fraction numerator 30 minus 15 over denominator 2 end fraction end cell row b equals cell 15 over 2 end cell row blank blank blank end table end style

Jadi, nilai begin mathsize 14px style a equals 5 over 2 end style dan begin mathsize 14px style b equals 15 over 2 end style.

b. Bentuk fungsinya:

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell f left parenthesis x right parenthesis end cell equals cell a x plus b end cell row blank equals cell 5 over 2 x plus 15 over 2 end cell row blank equals cell fraction numerator 5 x plus 15 over denominator 2 end fraction end cell end table end style

Jadi, bentuk fungsinya adalah begin mathsize 14px style f open parentheses x close parentheses equals fraction numerator 5 x plus 15 over denominator 2 end fraction end style.

c. Menentukan nilai begin mathsize 14px style f open parentheses negative 11 close parentheses end style.

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell f left parenthesis negative 11 right parenthesis end cell equals cell fraction numerator 5 open parentheses negative 11 close parentheses plus 15 over denominator 2 end fraction end cell row blank equals cell fraction numerator negative 55 plus 15 over denominator 2 end fraction end cell row blank equals cell fraction numerator negative 40 over denominator 2 end fraction end cell row blank equals cell negative 20 end cell end table end style

Jadi, nilai begin mathsize 14px style f open parentheses negative 11 close parentheses equals negative 20 end style.

Jawaban:Diketahui begin mathsize 14px style f open parentheses 3 close parentheses equals 15 end style dan begin itu jawaban nya ada pada gambar ya kalau sala tolong di maaf kanmathsize 14px style f open parentheses 5 close parentheses equals 20 end style, sehingga:begin mathsize 14px style f left parenthesis x right parenthesis equals a x plus b f open parentheses 3 close parentheses equals 15 space rightwards arrow 3 a plus b equals 15 space.... open parentheses 1 close parentheses f open parentheses 5 close parentheses equals 20 space rightwards arrow 5 a plus b equals 20 space.... open parentheses 2 close parentheses end style Eliminasi persamaan (1) dan (2).begin mathsize 14px style table row cell 3 a plus b equals 15 end cell row cell 5 a plus b equals 20 end cell row cell negative 2 a equals negative 5 end cell row cell a equals 5 over 2 end cell end table minus end style Subtitusi nilai begin mathsize 14px style a end style ke persamaan (1) atau (2)begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell 3 a plus b end cell equals 15 row cell 3 times open parentheses 5 over 2 close parentheses plus b end cell equals 15 row cell 15 over 2 plus b end cell equals 15 row b equals cell 15 minus 15 over 2 end cell row b equals cell fraction numerator 30 minus 15 over denominator 2 end fraction end cell row b equals cell 15 over 2 end cell row blank blank blank end table end style Jadi, nilai begin mathsize 14px style a equals 5 over 2 end style dan begin mathsize 14px style b equals 15 over 2 end style.b. Bentuk fungsinya:begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell f left parenthesis x right parenthesis end cell equals cell a x plus b end cell row blank equals cell 5 over 2 x plus 15 over 2 end cell row blank equals cell fraction numerator 5 x plus 15 over denominator 2 end fraction end cell end table end style Jadi, bentuk fungsinya adalah begin mathsize 14px style f open parentheses x close parentheses equals fraction numerator 5 x plus 15 over denominator 2 end fraction end style.c. Menentukan nilai begin mathsize 14px style f open parentheses negative 11 close parentheses end style. begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell f left parenthesis negative 11 right parenthesis end cell equals cell fraction numerator 5 open parentheses negative 11 close parentheses plus 15 over denominator 2 end fraction end cell row blank equals cell fraction numerator negative 55 plus 15 over denominator 2 end fraction end cell row blank equals cell fraction numerator negative 40 over denominator 2 end fraction end cell row blank equals cell negative 20 end cell end table end style Jadi, nilai begin mathsize 14px style f open parentheses negative 11 close parentheses equals negative 20 end style.Jawaban:Diketahui begin mathsize 14px style f open parentheses 3 close parentheses equals 15 end style dan begin itu jawaban nya ada pada gambar ya kalau sala tolong di maaf kanmathsize 14px style f open parentheses 5 close parentheses equals 20 end style, sehingga:begin mathsize 14px style f left parenthesis x right parenthesis equals a x plus b f open parentheses 3 close parentheses equals 15 space rightwards arrow 3 a plus b equals 15 space.... open parentheses 1 close parentheses f open parentheses 5 close parentheses equals 20 space rightwards arrow 5 a plus b equals 20 space.... open parentheses 2 close parentheses end style Eliminasi persamaan (1) dan (2).begin mathsize 14px style table row cell 3 a plus b equals 15 end cell row cell 5 a plus b equals 20 end cell row cell negative 2 a equals negative 5 end cell row cell a equals 5 over 2 end cell end table minus end style Subtitusi nilai begin mathsize 14px style a end style ke persamaan (1) atau (2)begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell 3 a plus b end cell equals 15 row cell 3 times open parentheses 5 over 2 close parentheses plus b end cell equals 15 row cell 15 over 2 plus b end cell equals 15 row b equals cell 15 minus 15 over 2 end cell row b equals cell fraction numerator 30 minus 15 over denominator 2 end fraction end cell row b equals cell 15 over 2 end cell row blank blank blank end table end style Jadi, nilai begin mathsize 14px style a equals 5 over 2 end style dan begin mathsize 14px style b equals 15 over 2 end style.b. Bentuk fungsinya:begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell f left parenthesis x right parenthesis end cell equals cell a x plus b end cell row blank equals cell 5 over 2 x plus 15 over 2 end cell row blank equals cell fraction numerator 5 x plus 15 over denominator 2 end fraction end cell end table end style Jadi, bentuk fungsinya adalah begin mathsize 14px style f open parentheses x close parentheses equals fraction numerator 5 x plus 15 over denominator 2 end fraction end style.c. Menentukan nilai begin mathsize 14px style f open parentheses negative 11 close parentheses end style. begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell f left parenthesis negative 11 right parenthesis end cell equals cell fraction numerator 5 open parentheses negative 11 close parentheses plus 15 over denominator 2 end fraction end cell row blank equals cell fraction numerator negative 55 plus 15 over denominator 2 end fraction end cell row blank equals cell fraction numerator negative 40 over denominator 2 end fraction end cell row blank equals cell negative 20 end cell end table end style Jadi, nilai begin mathsize 14px style f open parentheses negative 11 close parentheses equals negative 20 end style.Jawaban:Diketahui begin mathsize 14px style f open parentheses 3 close parentheses equals 15 end style dan begin itu jawaban nya ada pada gambar ya kalau sala tolong di maaf kanmathsize 14px style f open parentheses 5 close parentheses equals 20 end style, sehingga:begin mathsize 14px style f left parenthesis x right parenthesis equals a x plus b f open parentheses 3 close parentheses equals 15 space rightwards arrow 3 a plus b equals 15 space.... open parentheses 1 close parentheses f open parentheses 5 close parentheses equals 20 space rightwards arrow 5 a plus b equals 20 space.... open parentheses 2 close parentheses end style Eliminasi persamaan (1) dan (2).begin mathsize 14px style table row cell 3 a plus b equals 15 end cell row cell 5 a plus b equals 20 end cell row cell negative 2 a equals negative 5 end cell row cell a equals 5 over 2 end cell end table minus end style Subtitusi nilai begin mathsize 14px style a end style ke persamaan (1) atau (2)begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell 3 a plus b end cell equals 15 row cell 3 times open parentheses 5 over 2 close parentheses plus b end cell equals 15 row cell 15 over 2 plus b end cell equals 15 row b equals cell 15 minus 15 over 2 end cell row b equals cell fraction numerator 30 minus 15 over denominator 2 end fraction end cell row b equals cell 15 over 2 end cell row blank blank blank end table end style Jadi, nilai begin mathsize 14px style a equals 5 over 2 end style dan begin mathsize 14px style b equals 15 over 2 end style.b. Bentuk fungsinya:begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell f left parenthesis x right parenthesis end cell equals cell a x plus b end cell row blank equals cell 5 over 2 x plus 15 over 2 end cell row blank equals cell fraction numerator 5 x plus 15 over denominator 2 end fraction end cell end table end style Jadi, bentuk fungsinya adalah begin mathsize 14px style f open parentheses x close parentheses equals fraction numerator 5 x plus 15 over denominator 2 end fraction end style.c. Menentukan nilai begin mathsize 14px style f open parentheses negative 11 close parentheses end style. begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell f left parenthesis negative 11 right parenthesis end cell equals cell fraction numerator 5 open parentheses negative 11 close parentheses plus 15 over denominator 2 end fraction end cell row blank equals cell fraction numerator negative 55 plus 15 over denominator 2 end fraction end cell row blank equals cell fraction numerator negative 40 over denominator 2 end fraction end cell row blank equals cell negative 20 end cell end table end style Jadi, nilai begin mathsize 14px style f open parentheses negative 11 close parentheses equals negative 20 end style.

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Last Update: Sat, 28 Jan 23