Question

the perimeter of a triangle is 87 centimeters. if two sides are equally long and the third is 9 centimeters longer than the others find the length of teh three sides.

Answer 1

Perimeter is all sides added together so,
x+x+x+9=87

now solve for x

Answer 2

is it x=39?

Answer 3

or x=18

Answer 4

Not quite.
First add like terms

3x+9=87
then subtract 9 from both sides
3x=78
x=26