Question

x^2-20x=10 complete the square

Answer 1

x^2-20x-10=0
use the quadratic formula
http://www.mathsisfun.com/quadratic-equation-solver.html

Answer 2

Thank you!

Answer 3

It doesnt let me use the minus sign.

Answer 4

Complete the square means to complete the square. Like this:
x^2 - 20x is the square of what. Well, if we add + 100
x^2 - 20x + 100 = (x - 10)(x - 10).

So, we have
x^2 - 20x - 10 = x^2 - 20x - 10 + 100 - 100
= (x-10)^2 - 110
x = sqrt(110) + 10

The quadratic gives you:
20 +/- sqrt (400 + 40) / 2
= 10 + sqrt(110)

So it checks.

Answer 5

Thanks.