9514 1404 393
Answer:
8m³ -4m² +3m
Explanation:
The perimeter of a triangle is the sum of the lengths of its three sides. Here, you're given the perimeter and two of the sides. The third side will be the length that makes up the difference.
P = side 1 + side 2 + side 3
18m³ +2m² -m = (5m³ +3m² -2m) +(5m³ +3m² -2m) + side 3
18m³ +2m² -m = (10m³ +6m² -4m) + side 3 . . . . . collect terms
18m³ +2m² -m - (10m³ +6m² -4m) = side 3 . . . . . subtract (10m³ +6m² -4m)
m³(18 -10) +m²(2 -6) +m(-1 +4) = side 3 . . . . . . . . . group like terms
8m³ -4m² +3m = side 3