The length of a rectangle is one more that three times its width. if the perimeter is 42 inches, find the dimensions of the rectangle. show all work.

Let w=width
L= length
3w+1=l
Perimeter -2(l+w)
2(W+3w+1)=42
Divide both sides by 2
W+3w+1=21
Subtract 1
W+3w=20
Add like terms
4w=20
Divide both sides by 4
W=5
The width is 5 inches

3w+1=l
Input the width into the equation
3(5)+1=l
15+1=l
16=l
The length of the rectangle is 16 inches

The rectangle is 5 x 16 inches

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