The perimeter of a rectangle is 24mm. The length is 4mm less than triple the width. What are the dimensions of the rectangle

The length is equal to 8. The width is equal to 4.

2l + 2w = 24

l = 3w - 4

Because we have a value for l, we can plug it into the first equation to solve for the exact value of w.

2 (3w - 4) + 2w = 24

Distributive property.

6w - 8 + 2w = 24

Combine like terms.

8w - 8 = 24

Add 8 to both sides.

8w = 32

Divide both sides by 8.

w = 4

Now that we have a value for w, we can plug it into the second equation to solve for the exact value of l.

l = 3 (4) - 4

l = 12 - 4

l = 8