9514 1404 393
Answer:
6x -7 units
Step-by-step explanation:
Let c represent the length of the third side. The perimeter is the sum of the three side lengths.
P = a + b + c
(17x -5) = (3x +5) +(8x -3) +c
17x -5 = 11x +2 + c . . . . . . . . . . . . collect terms
6x -7 = c . . . . . . . . . . . . . . subtract 11x+2
The third side is 6x -7 units.
