用加减消元法解下列二元一次方程组 {x+2y=-2,7x-4y=4 {4x-3y=3,x/4+y/3=1/3

问题描述:

用加减消元法解下列二元一次方程组 {x+2y=-2,7x-4y=4 {4x-3y=3,x/4+y/3=1/3

1,x+2y=-2------(1)7x-4y=4 -----(2)(1)*2+(2),9x=0,x=0.2y=-2,y=-1x=0,y=-1.2,4x-3y=3------(1)x/4+y/3=1/3,3x+4y=4----(2)(1)*4+(2)*3,25x=24,x=24/25.96/25-3y=3,3y=96/25-3,y=7/25x=24/25,y=7/25