1. Perimeter
22a + 2(6a + 8) -4 = p
[I got 22a from 12a + 10a]
2. If p = 250, what is a?
22a + 2(6a + 8) - 4 = 250
Distributive property
22a + 12a + 16 - 4 = 250
Add like terms
34a + 12 = 250
Subtract 12 by both sides
34a = 238
Divide 34 by both sides
a = 7