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The area of a rectangle is 70ft^2. The length is 3 more than the width. Find the dimensions of the rectangle (width and length in feet).

 Jan 6, 2021
 #1
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+3

 

 

W+3=L

W(W+3)=70

Solve it as a quadratic.

 Jan 6, 2021
 #3
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0

Thank you!

SmartMathMan  Jan 8, 2021
 #2
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What two numbers multiply to make 70 and are different by 3. 

 

Take the first part first.  What two numbers can we multiply to make 70. 

 

If you don't see it intuitively, try them all.  Which one(s) is different by 3 ? 

 

 1 • 70    no... the diff is 69...  

 2 • 35    no... the diff is 33...  

 5 • 14    no... the diff is 9...  

 7 • 10    winner winner, chicken dinner!  

 

Melody's excellent answer suggested to set it up and solve as a quadratic equation, which is the best way to do it.  Notice, that factoring the quadratic takes you to the same question as the first line of this posting.  However, this problem was simple.  You might get into a situation where factoring would be difficult, if not impossible.  Then you need the proposition in quadratic form so you can use the quadratic formula. 

.

 Jan 6, 2021
 #4
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0

Thank you!

SmartMathMan  Jan 8, 2021

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