(a)

First, we subtract 2x on each side.

Then, we subtract 12 on each side.

The solution is -4.
(b)

We sum 7x on each side.

Then, we add 8 on each side.

At last, we divide the equation by 36.

The solution is 0.
(c)

First, we use the distributive property.

Then, we subtract 8x on each side.

Now, we add 10 on each side.

At last, we divide the equation by -4.

The solution is -6.5.