1. **State the problem:** Solve the equation $$3x(x + 1) - 7x(x + 2) = 6$$.
2. **Expand each term:**
$$3x(x + 1) = 3x^2 + 3x$$
$$-7x(x + 2) = -7x^2 - 14x$$
3. **Rewrite the equation with expanded terms:**
$$3x^2 + 3x - 7x^2 - 14x = 6$$
4. **Combine like terms:**
$$3x^2 - 7x^2 + 3x - 14x = 6$$
$$-4x^2 - 11x = 6$$
5. **Bring all terms to one side to set equation to zero:**
$$-4x^2 - 11x - 6 = 0$$
6. **Multiply entire equation by -1 to simplify:**
$$\cancel{-}4x^2 - \cancel{-}11x - \cancel{-}6 = 0 \Rightarrow 4x^2 + 11x + 6 = 0$$
7. **Use the quadratic formula:**
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
where $a=4$, $b=11$, and $c=6$.
8. **Calculate the discriminant:**
$$\Delta = b^2 - 4ac = 11^2 - 4 \times 4 \times 6 = 121 - 96 = 25$$
9. **Calculate the roots:**
$$x = \frac{-11 \pm \sqrt{25}}{2 \times 4} = \frac{-11 \pm 5}{8}$$
10. **Find each solution:**
- For $+$ sign:
$$x = \frac{-11 + 5}{8} = \frac{-6}{8} = -\frac{3}{4}$$
- For $-$ sign:
$$x = \frac{-11 - 5}{8} = \frac{-16}{8} = -2$$
**Final answer:**
$$x = -\frac{3}{4} \text{ or } x = -2$$
Solve Quadratic 7Ad618
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