
Brenda L. answered 11/06/17
Tutor
5
(32)
Calculus, Diffy Q, Pre-Calc, Algebra, Physics
The perimeter of a rectangle is 2 times the length plus 2 times the width: P = 2w + 2l. Here, the length is 2 less than 5 times the width: l = 5w - 2. Additionally, the perimeter is 32: P = 32. We need to plug both of these values into the perimeter equation and solve for width. Once we have the width, we can then solve for the length:
P = 2w + 2l
32 = 2w + 2(5w - 2) <--- Place 32 for P and 5w - 2 for l
32 = 2w + 10w - 4 <--- Foil the 2
32 = 12w - 4 <--- Combine the w terms
36 = 12w <--- Add 4 to both sides
3 = w <--- Divide by 12
Now that we have the width, we can find the length:
l = 5w - 2
l = 5(3) - 2 <---- Plug in the width we found earlier
l = 15 - 2 = 13
The length is 13 units.