Answer:a=4
Step-by-step explanation:
Simplifying
4a + -5 + 2a + 9 = 28
Reorder the terms:
-5 + 9 + 4a + 2a = 28
Combine like terms: -5 + 9 = 4
4 + 4a + 2a = 28
Combine like terms: 4a + 2a = 6a
4 + 6a = 28
Solving
4 + 6a = 28
Solving for variable 'a'.
Move all terms containing a to the left, all other terms to the right.
Add '-4' to each side of the equation.
4 + -4 + 6a = 28 + -4
Combine like terms: 4 + -4 = 0
0 + 6a = 28 + -4
6a = 28 + -4
Combine like terms: 28 + -4 = 24
6a = 24
Divide each side by '6'.
a = 4
Simplifying
a = 4