

Given figure is Triangle and its perimeter
.
Use the formula for the perimeter of the Triangle.
\The perimeter P of a Triangle is given by the formula
.
Where a, b, c are called as sides of the Triangle and a=b.
The values of a,b,c,p are 2x+2,2x+2,3x
3,15 are substitute in 
= 
Rearrange the terms using commutative property of addition:
.
= 
=
(Add:
)
(Simplify:
)
Apply to subtraction property of equality: Subtract 1 from each side.
\
(Subtract:
)
Apply to divison property of equality: Divide each side by 7.
\
(Cancel common terms)
The value of
is substitute in 2x+2,2x+2,3x
3.
2x+2
.
2x+2
.
3x
3
.
The value of
and sides of the Triangle are 6,6,3.