Substitute the 2x-10 in for I in the first equation:
5x+4(2x-10) =12
Distribute the 4:
5x+8x-40=12
Add 40 to both sides and combine the x terms:
13x=52
Divide by 13:
x=4
Plug the 4 into either equation for the x value:
y=2(4)-10
y=8-10
y=-2
Answer:
X=4
Y=-2
To check you can plug them into either one of the equations.