Answer:
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."
Answer:
100.
Step-by-step explanation:
We have been given an expression [tex]x^2-20x[/tex]. 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 [tex]a^2+2ab+b^2[/tex].
To complete a square we need to add the half the square of b that is [tex](\frac{b}{2})^2[/tex].
Upon looking at our given expression we can see that b is equal to 20, so [tex](\frac{b}{2})^2[/tex] would be:
[tex](\frac{b}{2})^2=(\frac{20}{2})^2=(10)^2=100[/tex]
[tex]x^2-20x+100=(x-10)^2[/tex]
Therefore, we must add 100 to our given expression to complete the square.
