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


Let the natural number be x,

Square of a number and diminished by 84


= (x2 + 84)


Thrice of 8 more than the given number


= 3(x + 8)


Equating both the equations,


x2 – 84 = 3(x + 8)


x2 – 84 = 3x + 24


x2 - 3x – 108 = 0


Using the quadratic formula,






The natural number . (* A natural number cannot be negative)


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