Formula used:(a - b)(a + b) = a2 - b2Calculation:\(4f(x) - f \left(\frac{1}{x}\right)=\left(2x+\frac{1}{x}\right)\left(2x-\frac{1}{x}\right)\)By using the above formula? \(4f(x) - f \left(\frac{1}{x}\right)=4x^2-\frac{1}{x^2}\) -----(1)Multiply by 4 on both sides\(16f(x) - 4f \left(\frac{1}{x}\right)=16x^2-\frac{4}{x^2}\) ----(2) Replace x with 1/x in equation (1)? \(4f(\frac{1}{x}) - f \left(x\right)=4(\frac{1}{x})^2-x^2\) -----(3)Add equation (2) & (3)? 16f(x) - f(x) = (16x2 - 4/x2) + (4/x2 - x2)? 15f(x) = 15x2 ? f(x) = x2 Put x = 2 ? f(2) = 4