My father taught me a method that I call, 'throwing some thing over the wall'. There is a sample equation for the first picture that shows you how it works. It's a great way to help isolate the variable and I hope that it works for you. The second picture contains the answers I got through the use of this method. I'm sorry for the messy handwriting; I was on a bus.
So for this one, 240 is Two Thirds of 360, which means in a shape with 6 points, it would move four points counterclockwise.
This would move G to the point H
C. H
Sum of linear pair of angles = 180°
so
<EFG + <GFH = 180°
2n + 21 + 4n + 15 = 180°
6n + 36 = 180°
6n = 144
n = 24
<EFG = 2(24) + 21 = 69°
<GFH = 4n + 15 = 4(24) + 15 = 111°
Answer:

Step-by-step explanation:

Identity used:


Now let us divide the modified expressions:
÷ 
we get:
