解方程组；1.x+y+z=26,x-y=1,2x-y+z=18 2.5x+y+z=1,2x-y+2z=1,x+5y-z=4.
问题描述：
解方程组；1.x+y+z=26,x-y=1,2x-y+z=18 2.5x+y+z=1,2x-y+2z=1,x+5y-z=4.
答
1) x+y+z=26---(1)x-y=1---(2)2x-y+z=18---(3)(1)+(2)==>2X+Z=27---(4)(1)+(3)==>3X+2Z=44---(5)(4)*2-(5)==>X=10,Z=7,Y=92) 5x+y+z=1--(1)2x-y+2z=1---(2)x+5y-z=4----(3)(1)+(2)==>7X+3Z=2---(4)(1)*5-(3)==>24X+6...