Question

Find a natural number whose square diminished by 84 is equal to thrice of 8 more than the give number.​

Answer 1

Answer:

Hence, the required number is 12.

Answer 2

❍ Let the natural number be x.

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★ According to given, x² - 84 = 3(x + 8)

➺ x² - 3x - 108 = 0

➺ x² - 12x + 9x - 108 = 0

➺ x(x - 12) + 9(x - 12) = 0

➺ (x - 12) (x + 9) = 0

➺ x - 12 = 0 or x + 9 = 0

➺ x = 12 or x = -9.

But x is a natural number, so we reject x = -9.

• Hence, the required number is 12.

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