Tentukan hasil pemfaktoran

1.a) 4x²-121 = 0
A + B = 0
A x B = 4.121= 484

maka A = 22 B = -22

(4x²+22x) (22x-121)
-2x(2x-11) 11(2x-11)

-2x+11 =0
x= -11/2

2x-11= 0
x = 11/2
________________
1.b) x²-7x-30=0
A + B= -7
A x B= -30
maka A = -10 dan B = 3

x-10 = 0
x = 10

x+3 = 0
x = -3
_______________
1.c) 3x²- x- 2 = 0
A + B= -1
A x B= -6
A = -3 dan B= 2

(3x²-3x)(2x-2)
3x(x-1)2(x-1)

3x+2 = 0
x = -2/3

x-1 =0
x= 1

__________________
2) 2x²-2x-12 = 0
A + B= -2
A x B= -24

A= -6 dan B = 4

(2x²-6x)(4x-12)
2x(x-3)4(x-3)

2x+4 = 0
x = -4/2 = -2

x-3 =0
x= 3

_______________________
3)5x² + 6x – 8
a = 5
b = 6
c = -8

-b ± √ b² – 4.a.c
_____________
2a
-6 ± √ 6²- 4.5.-8
______________
2.5
-6 ± √ 36 – (-160)
______________
10
-6 ± √ 36 +160
______________
10
-6 ± √ 196
_________
10
-6 ± 14
______
10

penyelesaian
(-6+14) =
______
10
= -6/10 +14/10 = 8/10 = 4/5

(-6-14) =
_____
10

= -6/10 – 14/10 = -20/10 = -2

HP = { x = -2 atau x = 4/5)