Answer:
84 cm
Step-by-step explanation:
Equilateral triangle have sides that measure the same
so
3x-2 = 18+x
Subtract x from each side
3x-2-x =18+x-x
2x-2 = 18
Add 2 to each side
2x-2+2 = 18+2
2x= 20
Divide by 2
2x/2 = 20/2
x = 10
The side measures18+x = 18+10 = 28
The perimeter is 3 times the length of one side
3*28 = 84
