Question

16(x-y)²-25(x+y)²

Answer 1

16(x-y)²-25(x+y)²
= (4x-4y)²-(5x+5y)²
= ( 4x-4y + 5x+ 5y ) ( 4x- 4y - 5x - 5y)
= (5x + y )( -x - 9y)
= - (5x + y )( x + 9y)

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器宇轩昂,且有慧根,
乃是万中无一的武林奇才.
潜心修习,将来必成大器，
鄙人有个小小的考验请点击在下答案旁的
"选为满意答案"

Answer 2

16(x-y)²-25(x+y)²
=[4(x-y)]^2-[5(x+y)]^2
=[4(x-y)+5(x+y)][4(x-y)-5(x+y)]
=-(9x+y)(x+9y)