解三元一次方程 {y=2x-1 {3x+y+5z=9 {x+2y=3z=6 {x+y+z=26 {x-y=1 {2x-y+z=18
问题描述:
解三元一次方程 {y=2x-1 {3x+y+5z=9 {x+2y=3z=6 {x+y+z=26 {x-y=1 {2x-y+z=18
答
{y=2x-1 (1)3x+y+5z=9 (2)x+2y+3z=6 (3)(2)*3-(3)*5得9x+3y+15z-5x-10y-15z=9*3-6*54x-7y=-34x-7(2x-1)=-34x-14x+7=-3-10x=-10x=1y=1z=1{x+y+z=26 (1)x-y=1 (2)2x-y+z=18 (3)(1)-(3)得x+y+z-2x+y-z=26-18-x+2y=8 (4)...