f) $2 x^{2}+3 x-20$

Step 1 ：Given the quadratic equation: \(2x^2 + 3x - 20 = 0\)

Step 2 ：Using the quadratic formula: \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\), where \(a = 2\), \(b = 3\), and \(c = -20\)

Step 3 ：Calculate the discriminant: \(169\)

Step 4 ：Find the roots: \(x_1 = 2.5\) and \(x_2 = -4.0\)

Step 5 ：Final Answer: The roots of the quadratic equation are \(\boxed{2.5}\) and \(\boxed{-4.0}\)