1. **State the problem:** Solve the quadratic equation $$2x^2 - 3x - 15 = -4x$$ using the quadratic formula and express the answer in simplest form.
2. **Rewrite the equation:** Move all terms to one side to set the equation to zero:
$$2x^2 - 3x - 15 + 4x = 0$$
Simplify the linear terms:
$$2x^2 + ( -3x + 4x ) - 15 = 0$$
$$2x^2 + x - 15 = 0$$
3. **Identify coefficients:** The quadratic equation is in the form $$ax^2 + bx + c = 0$$ where:
$$a = 2, \quad b = 1, \quad c = -15$$
4. **Quadratic formula:**
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
5. **Calculate the discriminant:**
$$b^2 - 4ac = 1^2 - 4 \times 2 \times (-15) = 1 + 120 = 121$$
6. **Substitute values into the formula:**
$$x = \frac{-1 \pm \sqrt{121}}{2 \times 2} = \frac{-1 \pm 11}{4}$$
7. **Find the two solutions:**
- For the plus sign:
$$x = \frac{-1 + 11}{4} = \frac{10}{4} = \frac{\cancel{10}}{\cancel{4}} = \frac{5}{2}$$
- For the minus sign:
$$x = \frac{-1 - 11}{4} = \frac{-12}{4} = \frac{\cancel{-12}}{\cancel{4}} = -3$$
8. **Final answer:**
$$x = \frac{5}{2} \quad \text{or} \quad x = -3$$
Quadratic Rational 54Ee09
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.