How do I solve for x in this quadratic equation x=8 x=-8?

Question

How do I solve x=8 x=-8

Answer 1

If I understand your question correctly, you want to take these roots and find the quadratic associated with them.  You can set these roots equal to 0 as follows

x-8=0

x+8=0

Then multiply the two factors using the distributive property or foil

(x+8)(x-8)=

x^2-8x+8x-64

simplify to x^2-64

In the graph you will see that the parabola crosses the x axis at 8 and -8 which is why x=8 and x=-8

Answer 2

x-8=0..........................1

x+8=0..........................2

Then multiply eq 1 and 2

(x+8)(x-8)=0

x^2-8x+8x-64=0

x^2-64=0

x^2=64

x^2=8^2

x=2