Mr. Jimenez has a pool behind his house that needs to be fenced in. The backyard is an odd quadrilat

Mr. Jimenez has a pool behind his house that needs to be fenced in. The backyard is an odd quadrilateral shape and the pool encompasses the entire backyard. The four sides are 1818a, 77b, 1111a, and 1919b in length. How much fencing? (the length of the perimeter) would he need to enclose the pool?

The perimeter P is found by adding all 4 sides:
P = 1818a + 77b + 1111a + 1919b

Group the a and b terms
P = (1818 + 1111)a + (77 + 1919b)
P = 2929a + 1996b