Answer :

justicehall2002

The picture is a bit blurry but the perimeter of a shape is the lengths added.

(4a - 2b) + (7a + 3) + (9a - 4) = perimeter, I added the sides together

Combine like terms to get:

4a + 7a + 9a = 20a

-2b is left along becuase there are no other like terms

3 - 4 = -1

The perimeter is 20a - 2b - 1

Answer:

20a - 2b - 1

Step-by-step explanation:

The perimeter is the sum of the 3 sides of the triangle, that is

perimeter = 9a - 4 + 7a + 3 + 4a - 2b ← collect like terms

                = (9a + 7a + 4a) - 2b + (- 4 + 3)

                = 20a - 2b - 1