Question

The perimeter of the equilateral triangle drawn below is 9b + 12.

Answer 1

An equilateral triangle has 3 equal sides
If the perimeter of a triangle is 9b+12 then one side equals 3b+4 (divide by 3 because there are 3 sides

In the big triangle there are 6 sides so multiply 3b+4 by 6
=18b+24

Answer 2

Not sure but 4(9b+12)= 36b+48