x²+8x+16-3xy-12y=(x+4)²-3y*(x+4)=(x+4)(x+4-3y)
x² + 8x + 16 - 3xy - 12y =
= (x² + 8x + 16) - (3xy + 12y) =
= (х + 4)² - 3у*(х + 4) =
= (х + 4)(х + 4 - 3у)
