Solve each of the following expressions for z using the quadratic formula and the x is small approximation. In which of the following expressions is the x is small approximation valid? Check all that apply. a. x²/(0.2-2) 1.3 x 10⁻⁴ b. x²/(0.2-2) 1.3 x 10⁻⁴ c. x²/(0.2-x)= 1.3 × 10⁻⁴ d. x²/(0.01-) = 1.3 x 10⁻⁴