Jawab:

Penjelasan dengan langkah-langkah:

fungsi f ( x ) = ax +b dengan

f ( - 2 ) = - 1 dan

f ( 5 ) = -15

a. tentukan nilai a dan b

b. rumus fungsi

c. f ( 3 )

a.

f(-2) = -1

-1 = a(-2) +b

-1 = -2a +b. . . . b = -1 + 2a

f(5) = -15

-15 = a(5) +b

-15 = 5a +b, dimana b = -1 + 2a

-15 = 5a + (-1 +2a)

-15 = 5a -1 +2a

5a + 2a = -15 +1

7a = -14

a = -2

b = -1 + 2a

b = -1 + 2(-2)

b = -1 + (-4)

b = -1 -4

b = -5

b. rumus fungsi = f(x) = ax +b

f(x) = -2x + (-5)

f(x) = -2x -5

c. f(3) => -2(3) -5

f(3) = -6 -5

f(3) = -11