Question

The sides of a pentagon are represented by x, x+2, x+5, 2x+2, and 3x-1. If the perimeter is 56, find the length of the longest side.
A)18 B)19 C)17 D)14

Answer 1

You add all the sides together getting
8x+8
Then you put it equal to 56
8x+8=56
You subtract 8 from each side
8x=48
You divide each by 8
x=6
Then you plug in for x
Its ends up that, 3x-1 makes the largest number
3(6)-1=17

Answer
C)17

Answer 2

perimeter= 56
⇒ x + x + 2 + x + 5 + 2x + 2 + 3x - 1= 56
⇒8x + 8= 56
⇒8x = 56-8
⇒x= 48/8
⇒x = 6
So the sides are
     x=6
     x+2=6 + 2 = 8
     x +3= 6+3= 9
     2x+2= (2*6)+2=12+2= 14
     3x-1= (3*6)-1= 18-1=17
Therefore, the answer is option C which is 17 units