If using the method of completing the square to solve the quadratic equation x^2-20x-25=0, which number would have to be added to "complete the square"?

-100

Step-by-step explanation:

x^2 - 20x - 25 = 0

In order to complete the square, we need it to follow the a^2 +/- 2ab + b^2 pattern

In this case since the coefficient before x is negative, it is (a-b)^2 = a^2 - 2ab + b^2

a = x

2ab = -20x

xb = -10x

b = -10

(x - 10)^2

Now since (-10)^2 is 100

We have to subtract 100 from our perfect square and subtract 25 since it is part of the original question

(x - 10)^2 - 100 - 25

Basically, you just have to add - 100 to the original equation to complete the square

4038

step-by-step explanation:

pleaze mark brainliest!