Question

the lenght of a rectangle is 2 cm less than 7 times the width. the perimeter is 60 cm . find the width and lenght

Answer 1

First, you want to establish your equations.

L=7W-2
P=60

This is what we already know. To find the width, we have to plug in what we know into P=2(L+W), our equation to find perimeter.

60=2(7W-2+W)

Now that we only have 1 variable, we can solve.

First, distribute the 2.
60=14W-4+2W

Next, combine like terms.

60=16W-4

Then, add four to both sides.

64=16W

Lastly, divide both sides by 16


W=4

To find the length, we plug in our width.

7W-2

7(4)-2

28-2

L=26