Answer:
11x - 25
Step-by-step explanation:
As the triangle is isosceles, two sides are equal to each other in length which is clearly marked on both sides.
So, the perimeter of the triangle is the sum of all the sides.
⇒ (4x - 17) + (4x - 17) + (3x + 9)
⇒ 4x + 4x + 3x - 17 -17 +9
⇒ 11x - 25