Question

Разложи на множители 3xy−21x−3y+21.

Answer 1

3x(y-7)-3(y-7)=(y-7)(3x-3)=3(y-7)(x-1)

Answer 2

3xy-21x-3y+21=3x*(y-7)-3*(y-7)=3*(x-1)*(y-7)