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2015-09-04T12:25:05+08:00

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The area of a rectangular library room is 60 squared meter.  Find the perimeter of the room given that its length is 3 meter more than thrice its width.

Representation:
Let width = x meter
     length = 3x + 3  meter
     Area = 60 m²

Area of Rectangle = Length × Width

60 = (3x+3) (x)
60 = 3x² + 3x

Equate to zero (this a quadratic equation)

3x² + 3x - 60 = 0

Solve by factoring:
3 (x²  + x + 20) = 0
3 (x-4) (x+5) = 0
  x-4 = 0                          x + 5 = 0
  x = 4                             x = -5

Choose the positive value x = 4
Width: x = 4 meters
Length: 3x + 3 
              = 3(4) + 3
              = 12 + 3
              = 15 meters

Perimeter of a rectangle: 2 (L) + 2 (W)
P = 2 (15 meters) + 2 ( 4 meters)
P = 30 meters + 8 meters
P = 38 meters

The perimeter of the rectangular library room is 38 meters.


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Thank you so much for your help. Can you add more problems?
I answered your other "ask a question" post
you're welcome :-)
2015-09-04T13:10:38+08:00

This Is a Certified Answer

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Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
   Two consecutive numbers have a sum of 47. What are the numbers?

Representation: Let x = 1st number
                        x + 1 = 2nd number

Equation: x + (x + 1) = 47

Solution: x + (x + 1) = 47
              x + x + 1 = 47
              2x + 1 = 47
              2x = 47 - 1
              2x    46
             ----  = ----   ⇒ x = 23 ; x + 1 = 24
              2       2 

Answer: The two consecutive numbers are 23 and 24.

Check: x + (x + 1) = 47
            23 + (23 + 1) = 47
            23 + 24 = 47
            47 = 47

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