Question

Resolva essas equacoes do segundo grau:
1- (x+6) (x-6)=85
2- x²+8x+7=0
3- x²-4x+4=9
4- 12x²-2x-10=0

Answer 1

1- x2-6x+6x-36=85
x2=85-36
x= +-√1

2- ∆=64-4.1.7
∆= 36
x=8+-√36\2
x= 8+6/2= 14/2=x1=7
x2=8-6/2=2/2=x2=1

3-∆=16-4.1.4
∆= 16-16
∆=0

∆= 144-4.(-2).(-10)
∆= 144-80
∆= 64
x=-2+-8/2.12
x=-2+8/24
x1=6/24= 1/4
x2= -10/24= -2/12= -1/6

Espero ter ajudado!
Tentei!