Quadratic Factoring 7D4092
1. **State the problem:** Solve the quadratic equation $$60x^2 + 25x - 15 = 0$$ by factoring.
2. **Formula and rules:** To solve by factoring, we first factor the quadratic expression into the product of two binomials and then set each factor equal to zero.
3. **Step 1: Factor out the greatest common factor (GCF):**
$$60x^2 + 25x - 15 = 5(12x^2 + 5x - 3)$$
4. **Step 2: Factor the quadratic inside the parentheses:**
We look for two numbers that multiply to $$12 \times (-3) = -36$$ and add to $$5$$.
These numbers are $$9$$ and $$-4$$ because $$9 \times (-4) = -36$$ and $$9 + (-4) = 5$$.
5. **Step 3: Rewrite the middle term using these numbers:**
$$12x^2 + 9x - 4x - 3$$
6. **Step 4: Factor by grouping:**
$$3x(4x + 3) - 1(4x + 3) = (3x - 1)(4x + 3)$$
7. **Step 5: Write the full factorization:**
$$5(3x - 1)(4x + 3) = 0$$
8. **Step 6: Set each factor equal to zero and solve for $$x$$:**
$$3x - 1 = 0 \Rightarrow x = \frac{1}{3}$$
$$4x + 3 = 0 \Rightarrow x = -\frac{3}{4}$$
**Final answer:** $$x = \frac{1}{3}, -\frac{3}{4}$$