Объяснение:

(6х²-3)+7х(6х²-3)-4у(6х²-3)=(6х²-3)*1+(6х²-3)*7х+(6х²-3)*(-4у)=

(6х²-3)*(1+7х+(-4у))=(6х²-3)*(1+7х-4у) =(3*2х²-3*1)*(1+7х-4у)

=3(2х²-1)*(1+7х-4у)