Question

Resposta para:
A) (x+3)^2 -1=8
B) x (x-3) = 28

Answer 1

a) (x+3)^2-1=8
x^2+2.x.3+3^3-1=8
x^2+6x+9-1-8
x^2+6x+9-9
x^2+6x=0
x(x+6)=0
x=0
x+6=0
x=0-6
x=-6
b) x(x-3)=28
x^2-3x=28
x^2-3x-28=0
delta=b^2-4ac
delta=(-3)^2-4.1.(-28)
delta=9+112
delta=121
x=-b-/+ raiz de delta/2a
x=-(-3)-11/2.1
x=3-11/2
x=-8/2
x=-4
x=-(-3)+11/2.1
x=3+11/2
x=14/2
x=7