Factorise x^2 + x - 12
2 answers:
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The length of the rectangle = 16 meters
The width of the rectangle = 10.5 meters
<u>Step-by-step explanation</u>:
Given that,
The Area of the rectangle is 273.
<u><em>Step 1</em></u><em> :</em>
Let, the width of the rectangle be 'x'
The length of the rectangle is 2x - 5
<u><em>Step 2</em></u><em> :</em>
Area of the rectangle = length width
273 = (2x - 5) x
273 = 2x^2 - 5x
<u><em>Step 3</em></u><em> :</em>
The equation formed is 2x^2 - 5x -273 = 0
a= coefficient of x^2 = 2
b= coefficient of x = -5
c = constant = -273
Find the roots of the equation, to find the width.
<u><em>Step 4</em></u><em> :</em>
Find the roots using factorizing method,
ac = 2-273 = -546 and b= -5
Factorizing -546 as -2621
The product of -2621 = -546
The sum of -26 + 21 = -5
<u><em>Step 5</em></u><em> :</em>
The roots of the equation 2x^2 - 5x -273 = 0 are x= -26/2 and x= 21/2
The values of x are x= -13 and x= 10.5
Since the width cannot be a negative value, neglect x= -13
<u><em>Step 6</em></u><em> :</em>
Therefore,
The width of the rectangle = 10.5 meters
The length of the rectangle = 2x-5
= 2(10.5) - 5
= 21 - 5
length = 16 meters