Answer:
x= 17cm
Step-by-step explanation:
given:
sides of a triangle:
x, x-5, 3x
perimeter= 80cm
perimeter of a triangle= side + side + side
80 = x + (x-5) + (3x)
80 = x + x + 3x -5 ------------->(rearranging the like terms together)
80 = 5x - 5
80+5 = 5x
85 = 5x
85/5 = x
17cm = x
9x−c
= 9x + − c
=−c+9x
