Question

A natural number is greater than three times it's square root by four.find the number.​

Answer 1

The answer is 16

This is the method :

Let the required natural number be x

It is mentioned that it is 4 more than 3 times its square root. Therefore the equation will be

x = 3√x + 4

√x = (x - 4)/3

Squaring both sides we get,

x = (x^2 + 16^2 - 8x) 9

x^2 - 17x + 16 = 0

On solving the equation by quadratic equation,

x = {-b +- √b^2 - 4(a)(c)}÷ 2a

x = 1 or x = 16

But if we check, 16 satisfies the answer

16 = 3×√16 + 4

16 = 3 × 4 + 4

16 = 16

So this is the answer '16'