The answer is B you're welcome :)
Area of a Triangle = 1/2(bh)
A = 1/2(5*3)
A = 15/2
A = 7.5
You want to make sure to factor each equation as much as you can first.
So just focus on the numerator first.

To factor the numerator:

factor out an x

factor out the rest completely.
Now for the denominator:


factor out a -4

factor out the rest.
This leaves you with:

Then you can simplify:

I'm not sure what you're supposed to find exactly, so if you need more help you can ask me (:
20/50=2/5=0.4=40%
2/5 or 0.40 or 40%
They're all equal.
Hope this helps :)
Yes, it is a rational number.