Question

一道七年级数学题速度求解！

x平方（3x+5y）平方-y平方（5x+3y）平方

Answer 1

x平方（3x+5y）平方-y平方（5x+3y）平方
=x²（3x+5y）²-y²（5x+3y）²
=[x（3x+5y）]²-[y（5x+3y）]²
=[x（3x+5y）+y（5x+3y）]*[x（3x+5y）-y（5x+3y）]
=[3x²+5xy+5xy+3y²]*[3x²+5xy-5xy-3y²]
=[3x²+10xy+3y²]*[3x²-3y²]
=9[x²+10xy/3+y²]*(x+y)(x-y)
=9(x+y/3)(x+3)(x+y)(x-y)
=3(3x+y)(x+3)(x+y)(x-y)

Answer 2

原式=
（3x²+5Xy)²-(5xy+3y²)²
(3x²+5xy+5xy+3y²)(3x²-3y²)
=3(3x²+10xy+3y²)(x+y)(X-y)
=3(3x+y)(x+3y)(x+y)(x-y)

Answer 3

9x四次方+21x平方y-2y平方x平方-25y四次方

Answer 4

9X的四次方+30X的三次方Y-30XY的三次方-9Y的四次方

Answer 5

最后答案 3（3x+y）(x+3y)(x+y)(x-y)