I first found x using the second equation :
-2x+4y=15
-2x = -4y+15
x =2y-7.5
Then, I substituted this value into the OTHER equation :
2x+5y=7
2(2y-7.5)+5y=7
4y-15+5y=7
9y=22
y=2.444
So you have you y value. Now, input this value into any one of the other equations (it doesn't matter which) to find x.
-2x+4y=15
-2x+4(2.444)=15
-2x+9.776=15
-2x=5.224
x=-2.612.
So the solution for this system of functions is (-2.612, 2.444).
