先化简后求值:3(-2x-x²y)-12x²y-(6y-9x²y+1).其中x与y互为相反数.
问题描述:
先化简后求值:3(-2x-x²y)-12x²y-(6y-9x²y+1).其中x与y互为相反数.
答
3(-2x-x²y)-12x²y-(6y-9x²y+1).
=﹣6x-3x²y-12x²y-6y+9x²y-1
=﹣6x-6y-6x²y-1
=﹣6﹙x+y﹚-6x²y-1
=﹣6x²y-1.