Concept: Let small charge in x be ?x and the corresponding change in y is ?y.\(\rm ? y = \rm \dfrac{dy}{dx}? x = f'(x) ? x \)Now that ?y = f(x + ?x) - f(x)Therefore, f(x + ?x) = f(x) + ?yCalculation: Given:f(x) = 3x2 + 3Let x + ?x = 3.01 = 3 + 0.01Therefore, x = 3 and ?x = 0.01f(x + ?x) = f(x) + ?y= f(x + ?x) = f(x) + f'(x)?x= f(3.01) = 3x2 + 3 + (6x)?x= f(3.01) = 3(3)2 + 3 + (6?3)(0.01)= f(3.01) = 30 + 0.18= f(3.01) = 30.18