Question 49878
2x-4y=7
4x+2y=9

multiply the 2nd equation by 2: 8x+4y=18
This gives you 2x-4y=7
               8x+4y=18
the y terms cancel out: 10x=25
divide both sides by 10: x=2.5

plug the x-value back into either original equation to solve for y.  For simplicity, I chose the 2nd one.
4x+2y=9
4(2.5)+2y=9
10+2y=9
2y=-1
y=-1/2 (or -0.5)

Check: 2(2.5)-4(-0.5)=7
5+2=7

So, the solution is (2.5, -0.5)