Answer:
P = (18a+10b+13) cm
Step-by-step explanation:
Given that,
A triangle has the lengths of (10a+9) cm, (8a—3) cm and (10b+7) cm.
We need to find an expression that represents the perimeter of the triangle.
Perimeter = sum of all sides
P = (10a+9) + (8a-3) + (10b+7)
Taking like terms together,
P = (10a+8a)+10b+(9-3+7)
= 18a+10b+13
Hence, the epresssion for the perimeter is (18a+10b+13) cm.