Multiply {x = 5, y = 4} by 4x-by=-2 to get b= 1 1/2.

Xiao Qiang thinks that A is -20/3 Xiao Liang and B is 1 1/2.

(2) Xiao Qiang misread A, but B did not misread it.

Multiply {x =-3, y =- 1} by {x=-3 times =-2 to get b= 10.

Xiao Liang is wrong about B, but A is not wrong.

Multiply {x = 5, y = 4} by ax+5y= 15 to get a=- 1.

The original equation is

-x+5y= 15 ( 1)

4x- 10y=-2 (2)

( 1)x2+(2)

-2x+4x=30-2

2x=28

x= 14，y=( 15+x)/5=29/5