Y=3x-4
Y=2x+5

Find out the X by doing the following:

3x-4=2x+5

3x-2x=5+4

x=9

Now if you substitute the x for 9:

Y=3x-4 = 3(9)-4 = 23
Y=2x+5 = 2(9)+5 = 23

There you go.