Answer:
d) 3x^3 - 2x^2 + 1 = 0
Explanation:
Option (d) 3x^3 - 2x^2 + 1 = 0 is not a quadratic equation in x.
A quadratic equation is a polynomial equation of degree 2 in one variable. In other words, the highest power of the variable in a quadratic equation is 2.
Option (d) has a highest power of x as 3, so it is not a quadratic equation. It is a cubic equation.
On the other hand, options (a), (b), and (c) are all quadratic equations in x.