Let's get this equation into a usable format, which is y=mx+b (where m is the slope and b is the y-intercept), before graphing.
First, we move our x terms onto one side, so that the y terms are on one side, and the x terms on another side. Keep in mind that this will negate (multiply by -1) the x term we move.
2y = -5x - 10
Then we isolate y. We'll do this by dividing by 2.
2y/2 = -5/2x - 10/2
y = -5/2x - 5
We now have the equation in y=mx+b format. We can now graph (it should look something like the one below).
Slope: -5/2
Y-Intercept: -5
:)