Question

The perimeter of a triangle is 24x+35 . One side is 8x-9 and the other side is 12x+20 . Find the missing side.

Answer 1

Let A, B and C be the three side lengths


So A+B+C = perimeter, which means A+B+C = P

Answer 2

The perimeter is 24x+35, so P = 24x+35

One side (say side A) is 8x-9 while the other (say side B) is 12x+20

So we go from

A+B+C = P

to

(8x-9)+(12x+20)+C = 24x+35

Answer 3

To find the third missing side, all you need to do is solve for C