solve:

1/4 (20- 4a) = 6 - a

a. -1

b. 0

c. all real numbers

d. no solution

First, we need to get rid of the parentheses. We do this by dividing by four. Remember that, because multiplication and division distribute, we will need to divide each term by four.

1/4 (20 - 4a) = 6 - a

20/4 - 4a/4 = 6 - a

5 - a = 6 - a

Now, we need to get "a" by itself, so we add a to both sides.

5 - a + a = 6 - a + a

Add like terms.

5 = 6

Because this is not a true statement, there is no solution.