用代入法解下列方程组:2x+3y=40,x-y=-5
问题描述:
用代入法解下列方程组:2x+3y=40,x-y=-5
答
x=y-5
2y-10+3y=40
y=10
x=5
答
2x+3y=40,
x-y=-5
2x+3y=40
3x-3y=-15
5x=25
x=5
5-y=-5
y=10
x=5
y=10