If an integer is added to its square, the sum is 90. Find the integer with the help of quadratic equation.

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1 Answers

Let the integer be ‘a’. 

Given, an integer is added to its square, the sum is 90 

⇒ a + a2 = 90 

⇒ a2 + 10a – 9a – 90 = 0 

⇒ a(a + 10) – 9(a + 10) = 0 

⇒ (a – 9)(a + 10) = 0 

⇒ a = -10, 9

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