What number must be added to the expression below to complete the square x2-20x?

100

Step-by-step explanation:

I believe you meant x^2 - 20x; " ^ " denotes exponentiation.

Take half the coefficient of the x term (which in this problem is -20).  We get -10.  Now square this, obtaining 100.

Adding 100 to x^2 - 20x "completes the square."

100.

Step-by-step explanation:

We have been given an expression . We are asked to find the number that must be added to the expression to complete the square.

We know that a perfect square is in form .

To complete a square we need to add the half the square of b that is .

Upon looking at our given expression we can see that b is equal to 20, so would be:

Therefore, we must add 100 to our given expression to complete the square.

+25 = x

step-by-step explanation:

here x is the hypotenuse of a right triangle whose legs are 7 and 24.   by the pythagorean theorem, 7² + 24² must equal x²:

x² = 49 + 576 = 625.   thus, x = +√625 = +25 = x