Question

2x(x+5)=100
2x^2+10x=100
-10X on each side
2x^2=100-10x
divide by 2
x^2=50-5x
now what?

Answer 1

Well, what are you trying to find? The 0s, aka: roots?

Answer 2

what is X

Answer 3

x is anything. You probably want the roots. That is the typical thing.

Set it = to 0 and factor.

Answer 4

See, if you get it in the form of:
\((x\pm a)(x\pm b)=0\)
Then you can set each factor to 0. Why? Because 0 times anything is 0. That means if any factor is 0 then the entire thing is 0. That lets you solve for the 0s or roots of the equation.

If you were to graph the equation, this would be the place where the curve touched the x axis and y was 0.