5a/2x + 7/10

What do you want to do with it?

Are you going to add them?
Did you mean it the way you typed it, or did you mean 5a/(2x) + 7/10 ?
I suspect it is the latter.

then LCD = 20x

= (5a(5) + 14x)/(20x)
= (25a + 14x)/(20x)