几道数学题(解方程组)1.2x+3y=73x-2y=82.6x+5y=203x+4y+253.2x+3y=44x-5y=64.7x+3y+44x-3y=7

几道数学题(解方程组)1.2x+3y=73x-2y=82.6x+5y=203x+4y+253.2x+3y=44x-5y=64.7x+3y+44x-3y=7
几道数学题(解方程组)
1.2x+3y=7
3x-2y=8
2.6x+5y=20
3x+4y+25
3.2x+3y=4
4x-5y=6
4.7x+3y+4
4x-3y=7

几道数学题(解方程组)1.2x+3y=73x-2y=82.6x+5y=203x+4y+253.2x+3y=44x-5y=64.7x+3y+44x-3y=7
1.1式×2+2式×3
13x=38
x=38/13
y=5/13
2.1-2*2
-3y=-30
y=10
x=-5
3.x=19/11 y=2/11
4.x=1 y=-1