The formula of a primeter of a rectangle: P = 2(l + w)
We have l = 2d - 3 and w = 3c. Substitute:
P = 2(2d - 3 + 3c) use distributive property
P = (2)(2d) + (2)(-3) + (2)(3c)
P = 4d - 6 + 6c
Answer: P = 6c + 4d - 6.
The formula of a perimeter of a tringle: P = x + y + z
We have x = 7a - 3, y = 9a - 4, z = 4a - 2b. Substitute:
P = (7a - 3) + (9a - 4) + (4a - 2b) = 7a - 3 + 9a - 4 + 4a - 2b
combine like terms
P = (7a + 9a + 4a) - 2b + (-3 - 4) = 20a - 2b - 7
Answer: P = 20a - 2b - 7.