Chapter 1, Equations and Inequalities - 1.3 Solve Linear Equations - 1.3 Exercises - Skill Practice - Page 22: 54

$x=5$ Side 1: $2x-2=8$ Side 2: $2x-2=8$ Side 3: $10-x=5$ Side 4: $10-x=5$

First, we add up all the side lengths: Perimeter $=(2x-2)+(2x-2)+(10-x)+(10-x)$ $=2x+16$ Then we set $2x+16$ equal to 26 and solve: $2x+16=26$ $2x=10$ $x=5$ Finally, we plug $x=5$ into the expressions for all of the sides: Side 1: $2x-2=(2\times5)-2=10-2=8$ Side 2: $2x-2=(2\times5)-2=10-2=8$ Side 3: $10-x=10-5=5$ Side 4: $10-x=10-5=5$