Question

need help : Factor completely x^2+7xy-144y^2

Answer 1

What are the factors of 144

1 * 144
2 * 72
3 * 46
4 * 36
6 * 24
8 * 18
9 * 16
12 * 12

Which pair subtracts to get you 7?

Answer 2

\[x^2+7xy-144y^2=x^2+16xy-9xy-144y^2=\]
\[=x(x+16y)-9y(x+16y)=(x+16y)(x-9y)\]