Jawaban:

1)..Bentuk umum persamaan kuadrat

ax² + bx + c = 0

Persamaan x² - 5x - 12 = 0

a = 1

b = -5

c = -12

Jumlah akar

= -b/a

= -(-5)/1

= 5

Hasil kali

= c/a

= -12/1

= -12

jadi jawabannya adalah -12.

2)..x1 = 2/3

x2 = -1

x1 + x2

= 2/3 + (-1)

= 2/3 - 3/3

= -1/3

x1.x2

= 2/3. (-1)

= -2/3

Persamaan kuadrat

x² - (x1+x2)x+ (x1.x2) = 0

x² - (-1/3)x+ (-2/3) = 0

x² + 1/3x - 2/3 = 0

= 3x² + x - 2 = 0

3).x² + 5x - 12 = 0

a = 1

b = 5

c = -12

D = b² - 4ac

D=5²-4(1)(-12)

D = 25 +48

D = 73

Karena D > 0, maka persamaan tersebut memiliki 2 penyelesaian

4).2x² + 6x - 7 = 0

D = b² - 4ac

D=6²-4(2)(-7)

D = 36 + 56

D = 92

x² - 8x + c = 0

D = 92

b² - 4ac = 92

(-8)² - 4(1)(c) = 92

64 - 4c = 92

-4c = 92 - 64

-4c = 28

c = -7

•Answer by : Hikaru Raido✨

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