Question

The natural number is three times greater than its square root by 4. What is the number?

Answer 1

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