You are finding the perimeter, which has double of each side length given.
Note: P = perimeter
2(5x - 1) + 2(2x + 1) = P
Distribute 2 to each monomial in the given parenthesis
2(5x - 1) = 10x - 2
2(2x + 1) = 4x + 2
10x - 2 + 4x + 2 = P
combine like terms.
P = 10x + 4x - 2 + 2
P = 14x
C) 14x, is your answer
hope this helps
