Question

What number must you add to complete the square?

Answer 1

Whenever you complete a square, you're really taking this:

(x+b)^2=x^2+2bx+b^2 [/tex]

And equating roots. Here, the b is clearly 11 (2b=22 implies b=11), so that means we want 121 as our ending number. That means we should add 121 to both sides to get:

$x^2+22x+121=9+121 \implies \\ (x+11)^2=130$