Draw a diagram!
I let the length be L feet and the width W feet. Since the perimeter is 14 feet
The problem says "The length of the bill board is 6 feet greater than triple the width." If the width is W feet what is triple the width? What is 6 feet more that triple the width? This value is L. Substitute this value for L in the equation above and solve for W.
Do you know the formula for the perimeter of a rectangle of lenght L and width W?? If not, draw one and count how many "long edges" and how many "wide edges" make up the entire boundary.
the length of the bill board is 6 feet greater than triple the width.
If the width is W, what is triple the width?
What is 6 more than triple the width?
You should now have two linear equations, each of the form
? L + ? W = ? or ?L = ?W + ? or ?W = ?L + ?
(each question mark stands for something different.)
Now try to use algebra to turn one of these equations into an
L = aW + b
(You can do anything to one side provided you do it to the other as well. So if one equation was (it isn't)
3L + 6W = 21
you could divide both sides by 3 to get
L + 2W = 7
and subtract 2W from both sides to get
L = 7 - 2W.
Now substitute [in this case; you'll do it differently] (7-2W) for L inthe other equation to get an equation with only W's in. Solve this in the same way, using algebra to put it into a form like
Finally, plug that back in to get a value for L.
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