解道初一方程组

4x+y-1=0 (1)
2y-2x+1=0(2)
(2)*2得4y-4x+2=0(3)
(3)+(1)得5y+1=0
y=-0.2
把y=0.2代入(1),得-0.2+4x-1=0
x=0.3
x=0.3
y=-0.2

4x+y-1=0=》y=1-4x
代入2y-2x+1=0
=》2（1-4x）-2x+1=0
=>2-8x-2x+1=0
=>x=3/10代入：y=1-4x
y= -1/5

4x+y-1=0
y=1-4x代入方程2y-2x+1=0
2（1-4x）-2x+1=0
2-8x-2x+1=0
10x=3
x=0.3
将x=0.3代入方程4x+y-1=0
y=-0.2
所以方程的解为x=0.3，y=-0.2

2y-2x+1=0两边同时乘以2得
-4x+4y+2=0再与4x+y-1=0 相加得
5y+1=0
y=-1/5代入4x+y-1=0
得4x=1+1/5
x=3/10

把2y-2x+1=0 变换为4y-4x+2=0
然后用它加去4x+y-1=0 得5y+1=0 y=-1/5
把它代入2y-2x+1=0得x=3/10

4x+y-1=0 (1)
2y-2x+1=0(2)
(2)x2+(1)
5y=-1 y=-1/5

x=3/10