1.已知x-4y=3x+4y=30,求x、y的值x=15,y=-4/152.若|3x+2y-4|+|3y-2x+5|=0,求x+y的值13/15

Question

1.已知x-4y=3x+4y=30,求x、y的值
x=15,y=-4/15
2.若|3x+2y-4|+|3y-2x+5|=0,求x+y的值
13/15

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