Combine and simplify the following radical expression 1/3^3radical81

Can someone explain the elimination method to me for this problem?

Sadie computes the perimeter of a rectangle by adding the length, l, and width, w, and doubling this sum. eric computes the perimeter of a rectangle by doubling the length, l, doubling the width, w, and adding the doubled amounts. write an equation for sadie’s way of calculating the

1. are the triangles similar and if so why? what is the value of x? show your work.