化简求值:2xy-1/2(4xy-8x^2y^2)+2(3xy-5x^2 y^2),其中x=2/3,y=-2/3提示:正确答案是-12,
问题描述:
化简求值:2xy-1/2(4xy-8x^2y^2)+2(3xy-5x^2 y^2),其中x=2/3,y=-2/3
提示:正确答案是-12,
答
原式=2xy-(2xy-4x2y2)+(6xy-10x2y2) =2xy-2xy+4x2y2+6xy-10x2y2 =6xy-6x2y2将x=2/3,y=-2/3代入,则原式=很明显,你可能抄错题了哦,我检查过很多遍了,步骤没有错,应该是题错了望采纳哦~