A triangle has side lengths of (10b+3c)(10b+3c) centimeters, (4b+4d)(4b+4d) centimeters, and (5d+7c)(5d+7c) centimeters. Which expression represents the perimeter, in centimeters, of the triangle?

To find the perimeter of a triangle we have to add the lengths of all the sides.
Perimeter = (10b+3c)+ (4b+4d) + (5d+7c)
Simplify by combining like terms
10b+3c+4b+4d+5d+7c
10b+4b+4d+5d+3c+7c
14b+9d+10c