Expert: Scott A Wilson - 10/20/2011

Question
2x-3y=7
3x y=5

Answer
I will assume the equations are 2x-3y=7 and 3x+y=5.

Take the 2nd equation, 3x+y=5, and subtract 3x from both sides.  This gives y=5-3x.

Put this into the 1st equation and solve for x.
This gives 2x - 3(5-3x) = 7.
Multiplying out gives 2x - 15 + 9x = 7.
Combining terms and adding 15 to both sides gives 11x = 22.
Dividing by 11 gives x = 2.

Reputting this back in the 1st equation gives 2*2 - 3y = 7, so 4 - 3y = 7.
Subtracting 4 from both sides gives -3y = 3, so y = -1.

Checking the 2nd equation gives 3(2) + -1 = 5, and that is correct.