Solve the simultaneous equations: 4X+6Y=4 and 7X+5Y=12.5

There are two ways of solving this problem:
Method 1: substitution.
Make X (or Y) the subject of one equation: X= (4-6Y)/4
Substitute this into the other equation:
7/4*(4-6Y) +5Y=12.5
Simplify and rearrange
-5.5Y= 5.5Y Y=-1
Substitute this in to find X
4X-6=4 X=2.5
Method 2:Elimination
Make it such that the coefficent of Y (or X), is the same in both equations
20X+30Y=20 42X+30Y=75
Subtract (or add, depends on the sign) the two equation from each other to eliminate Y
22X=55 X=2.5
Find Y
10+6Y=4 Y=-1