已知3(x+2)的平方和2乘x-y+1的绝对值互为相反数,求5x的平方y-﹛2x的平方y-[3xy的平方-(4xy的平方-2x平方y]﹜

∵3(x+2)²和|2(x-y+1)|互为相反数即3(x+2)²=-2(x-y+1)|∴x+2=0x-y+1=0∴x=-2,y=-15x²y-{2x²y-[3xy²-(4xy²-2x²y)]}=5x²y-[2x²y-(3xy²-4xy²+2x²y)]=5x&#...是2|x-y+1|结果是一样的，把开头地方变一下就可以了 ∵3(x+2)²和2|(x-y+1)|互为相反数 即3(x+2)²=-2|(x-y+1)|∴x+2=0 x-y+1=0∴x=-2，y=-1有疑问请追问，满意请采纳