Question

1.已知x-4y=3x+4y=30,求x、y的值

Answer 1

x-4y=30

x+4y=30

2x=60

x=30

y=0

3x+2y-4=0

3y-2x+5=0

3x+2y=4

3y-2x=-5

x+5y=-1

2x+10y=-2

13y=-7

y=-7/13

x=-1+35/13

x=22/13