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Question
If the area of a square is 400 m2, then find the side of the square by the method of factorization.
Solution
Let the side of the square be x meter.
Then, Area of a square = side × side = x × x = x2
According to the question,
x2 = 400
⇒ x2 – 400 = 0
⇒ x2 – (20)2 = 0
⇒ (x + 20) (x – 20) = 0 ......[∵ a2 – b2 = (a + b) (a – b)]
⇒ (x + 20) = 0 or (x – 20) = 0
⇒ x = – 20 or x = 20
Because a square's side cannot be negative, x = 20.
As a result, the side of the square is 20 m.
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