Question

1.在2元1次5x+6y=30,若x与y时相等的,则x=什么?若x与y是相反数,则y等于什么?

Answer 1

1.X=Y时,X=11/30,x与y是相反数时,Y=30

2.因为（4x+3y-1)的2次方+|2x-y+7|≤0

且（4x+3y-1)的2次方≥0,|2x-y+7|≥0,所以4x+3y-1=0,2x-y+7=0

所以X=0.1,Y=0.2

3.⑴|x|+y=2

⑵|x|+2y=0

⑴:|x|+y=2

|x|=2-y

将⑴代入⑵

⑵:2-y+2y=0

y=-2

将y=-2代入⑴

|x|=4

x=±4