SOLUTION: Hello, How do you set up an equation in algebra to show that the width of a rectangle is 3 ft shorter than the length and that the perimeter of the rectangle is 86 feet? 86=

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Question 590348: Hello,
How do you set up an equation in algebra to show that the width of a rectangle is 3 ft shorter than the length and that the perimeter of the rectangle is 86 feet?
86=3w -6
I am soooo confused! Please help!
bmccain@wowway.com
Found 2 solutions by Theo, scott8148:
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
L = length of rectangle
W = width of rectangle
W = L - 3
P = perimeter = 86 feet.
formula for perimeter:
2L + 2W = 86
substitute L-3 for W to get:
2L + 2(L-3) = 86
simplify by removing parentheses to get:
2L + 2L - 6 = 86
combine like terms to get:
4L - 6 = 86
add 6 to both sides to get:
4L = 92
divide both sides by 4 to get:
L = 23
since W = L - 3, then:
W = 20
formula for perimeter is:
2L + 2W = 86
substitute for L and W to get:
2*23 + 2*20 = 86
simplify to get:
46 + 40 = 86
combine like terms to get:
86 = 86
values for L and W are good.

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
it's actually two equations, because there are two unknowns (length and width)

2L + 2W = 86 ___ L + W = 43

W = L - 3

you can solve the system of equations by substitution or elimination

substituting ___ L + (L - 3) = 43