计算下列各题,
问题描述:
计算下列各题,
(5x+y)(3x-5x)-(4x-y)(4y+x)
已知(x-y)^2=625/36,x+y=7/6,求xy的值
解方程:(3x+2)(x-1)=3(x-1)(x+1)
答
1.(5x+y)(3x-5y)-(4x-y)(4y+x)=15x²-25xy+3xy-5y²-(16xy+4x²-4y²-xy)=15x²-22xy-5y²-15xy-4x²+4y²=11x²-37xy-y²2.∵x+y=7/6∴x²+2xy+y²=49/36①∵(x-y...