how do i set up and solve?

Question

The length of one of the equal legs of an isosceles triangle is 8 cm less than 4 times the length of the base. If the perimeter is 29 cm, find the length of one of the equal legs. Define variables, set up equation and solve.

Answer 1

l=4x-8
therefore, 2l+x=29
8x-16+x=29
9x-16=29
9x=45
x=5
l=12

Answer 2

Set the base equal to B.
Set the equal side lengths equal to L.

So L=4B-8

Perimeter=29=B+(4B-8)+(4B-8)

29=9B-16
9B=45
B=5

So L=4(5)-8=12