When solving the binary linear equations ax+by=3 cx-5y=7, Xiaoming correctly solved x= 1 y=-2, Xiaoyan misread C and solved x=-3 y= 1 to find the value of abc.

Substitute X= 1 Y=-2.

2B=3

C+ 10=7 C=-3

Substitute X= -3 Y= 1.

-3A+B=3

2B=3

-3A+B=3

The solution is A= -9/5 B=-12/5.

So ABC = (-9/5) * (-12/5) * (-3) =-324/25.

AB is correct, because it is only C, just take C in the first equation to calculate.

Hope to adopt \ (o)/~