1. **State the problem:** Solve the quadratic equation $$15b^2 - 8b - 3 = -4$$ for $b$ using the quadratic formula.
2. **Rewrite the equation in standard form:** Move all terms to one side to get zero on the other side:
$$15b^2 - 8b - 3 + 4 = 0$$
$$15b^2 - 8b + 1 = 0$$
3. **Identify coefficients:** Here, $a = 15$, $b = -8$, and $c = 1$.
4. **Recall the quadratic formula:**
$$b = \frac{-B \pm \sqrt{B^2 - 4AC}}{2A}$$
where $A$, $B$, and $C$ are coefficients from the quadratic equation $Ax^2 + Bx + C = 0$.
5. **Substitute the values:**
$$b = \frac{-(-8) \pm \sqrt{(-8)^2 - 4 \times 15 \times 1}}{2 \times 15}$$
6. **Simplify inside the square root:**
$$b = \frac{8 \pm \sqrt{64 - 60}}{30}$$
$$b = \frac{8 \pm \sqrt{4}}{30}$$
7. **Calculate the square root:**
$$b = \frac{8 \pm 2}{30}$$
8. **Find the two possible solutions:**
$$b = \frac{8 + 2}{30} = \frac{10}{30}$$
$$b = \frac{8 - 2}{30} = \frac{6}{30}$$
9. **Simplify the fractions:**
$$b = \frac{\cancel{10}}{\cancel{30}} = \frac{1}{3}$$
$$b = \frac{\cancel{6}}{\cancel{30}} = \frac{1}{5}$$
**Final answer:**
$$b = \frac{1}{3} \text{ or } b = \frac{1}{5}$$
Quadratic Rational C7300D
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.