Jawaban:

A. x^2 -5x -6 =0

faktorisasi : ( x + 1 ) ( x - 6) =0

x1 = x+1 =0

x = -1

x2 = x-6 =0

x = 6

persamaan kuadrat : a= 1 b= -5 c= -6

akar persamaan kuadrat : x1 + x2 = -b/a

-1 + 6 = -(-5) / 1

= 5

x1 . x2 = c/a

-1 . 6 = -6 /1

= -6

B. 4x^2 + 4x =15

= 4x^2 + 4x -15 = 0

faktorisasi : ( 2x + 3) (2x -5) =0

x1 = 2x+3 =0

2x= -3

x = -3/2

x2 = 2x -5 =0

2x= 5

x= 5/2

persamaan kuadrat: a= 4 b= 4 c= -15

akar persamaan kuadrat:

x1 + x2 = -b/a

-3/2 + 5/2 = -4/4

x1 . x2 = c/a

-3/2 . 5/2 = 15/4

C. x^2+4x-12=0

faktorisasi :

( x + 6 ) ( x -2 ) = 0

x1 = x + 6 =0

x= -6

x2 = x - 2 =0

x = 2

persamaan kuadrat : a= 1 b= 4 c= -12

akar persamaan kuadrat

x1 + x2 = -b/a

-6 + 2 = -4/ 1 = -4

x1 . x2 = c/a

-6 . 2 = -12 . 1 = -12