若x-7的绝对值等于0,y+2的绝对值等于0,z的绝对值等于4且xyz大于0,求2x+2y-yz的值

题目

若x-7的绝对值等于0,y+2的绝对值等于0,z的绝对值等于4且xyz大于0,求2x+2y-yz的值

答案

｜x-7｜=0,∴ x=7;
｜y+2｜=0,∴ y=-2;
｜z｜=4,且xyz＞0,∴ z=-4;
则：2x+2y-yz=2×7 + 2×(-2) - (-2)×(-4) = 14 - 4 - 8 = 2