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The perimeter of the quadrilateral is 46 centimeters. Find the length of each side.

X+5
X+8
3x-2
x²-3x

User Newtopian
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1 Answer

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Solution:

Perimeter of quadrilateral = sum of all the four sides

  • First side = x + 5
  • Second side = x + 8
  • Third side = x-2
  • Fourth side = x²-3x
  • x + 5 + x +8 + 3x-2 + x² - 3x = 46

Combining like terms,

  • x² + x + x + 3x - 3x + 5 + 8 -2 = 46
  • x² + 5x - 3x + 13 - 2 = 46
  • x² + 2x + 11 = 46
  • x² +2x = 46 - 11
  • x² + 2x = 35
  • x² + 2x - 35 = 0

By splitting middle term,

  • 7x × (-5x) = 35
  • 7x + (-5x) = 2x
  • x² + 7x - 5x - 35 = 0
  • x (x +7) - 5 (x +7) = 0
  • (x -5)(x + 7) = 0

solving for x

x - 5 = 0, x = 5 or

x + 7 = 0, x = - 7

We will take postive value of x, i.e 5.

First side = x + 5

= 5 + 5 = 10

Second side = x + 8

= 5 + 8 = 13

Thrid side = 3x-2

= 3(5) - 2

= 15 - 2 = 13

Fourth side = x²-3x

= 5² - 3(5)

= 25 - 15 = 10

User Lugarini
by
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