You haven't told us what the question is, but I'll bet you need to find the value of 'y'.
I hope that's your task. Now I shall go ahead and solve the problem that I have invented.
Here's the easiest way to do that:
You said . . . . . 10 = 4y
Divide each side by 4. Then it says . . . 10/4 = y
That's all you need, right there. Just simplify the left side . . . 2.5 = y