Answer:
(2l + 2w) + (a + b + c)
Explanation:
The formula for the perimeter of a rectangle is
P = 2l + 2w
so if you substitute, it becomes
P = 2(12) + 2(2)
= 24 + 4
= 28
For the perimeter of a triangle the correct formula would be
P = a + b + c
The missing side in the triangle is 3 because 15 - 12 is 3.
If you substitute, it becomes
P = 2 + 3 + 6
P = 11
If we add both perimeters together we get the full perimeter of the figure which is
28 + 11 = 39
I am not sure if you wanted the answer as well but just in case :)