Question

16(x-y)的平方-25(x+y)的平方

Answer 1

16(x-y)的平方-25(x+y)的平方
=（4x-4y+5x+5y）(4x-4y-5x-5y) 根据平方差公式
=(9x+y)(-x-9y)
=-9x^2-82xy-9y^2

^2表示平方

Answer 2

16(x-y)的平方-25(x+y)的平方
=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]
=(9x+y)(-x-9y)

Answer 3

• -369X²﹣1600XY﹣369Y²

Answer 4

=(4x-4y)^2-(5x+5y)^2
=(4x-4y-5x-5y)(4x-4y+5x+5y)
=-(x+9y)(9x+y)

Answer 5

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