平法差公式计算 (5x+3y)(3y-5x)-(4x-y)(4y+x)
问题描述:
平法差公式计算 (5x+3y)(3y-5x)-(4x-y)(4y+x)
答
(5x+3y)(3y-5x)-(4x-y)(4y+x)
=(3y+5x)(3y-5x)-(4x-y)(x+4y)
=9y^2-25x^2-(4x^2+16xy-xy-4y^2)
=9y^2+4y^2-25x^2-4x^2-15xy
=13y^2-29x^2-15xy