求4x-9z=17 3x+y+15z = 18 x+2y+3z=18 的值

问题描述:

求4x-9z=17 3x+y+15z = 18 x+2y+3z=18 的值

4x-9z=17 (1)3x+y+15z = 18 (2)x+2y+3z=18 (3)由(2)*2-(3)得6x+2y+30z-x-2y-3z=36-185x+27z=18 (4)由(1)*3+(3)得12x-27z+5x+27z=51+1817x=69x=69/17y=262/51z=-13/153题目有误,求得x、y、z值不能满足3个方程...