Question

(3x-6)(3x+6)-3(2x-4)=?

Answer 1

$displaystyle tt (3x-6)(3x+6)-3(2x-4)=(3x)^2-6^2-3cdot2x-3cdot(-4)=\\ displaystyle tt =9x^2-36-6x+12=bold{9x^2-6x-24}$