Question 737414
Short side =x
Longer side =11 more than x= x+11

Perimeter =2*short+2*long= 2x+2(x+11)=50

{{{2x+2(x+11)=50}}}simplify with distribution and adding like terms on the left

{{{2x+2(x+11)=2x+2x+22=4x+22}}}

{{{4x+22=50}}}
Now to get x alone.
Subtract 22 from each side.
{{{4x=28}}}. 
Divide both sides by 4 to get x= 7

Go back to the top
Short side = x = 7
Long side = x+11 = 7+11=18

Check: P: 2(7) +2(18)=14+36=50.