1. **State the problem:** Simplify the expression $$\frac{10c + c^2 - 3c^3}{5c^2 - 6c - 8}$$.
2. **Rewrite the expression:** Arrange terms in descending powers of $c$ for clarity:
$$\frac{-3c^3 + c^2 + 10c}{5c^2 - 6c - 8}$$
3. **Factor the numerator:** Factor out $c$ first:
$$c(-3c^2 + c + 10)$$
Now factor the quadratic inside parentheses:
Find two numbers that multiply to $-3 \times 10 = -30$ and add to $1$.
These are $6$ and $-5$.
Rewrite:
$$-3c^2 + 6c - 5c + 10 = (-3c^2 + 6c) + (-5c + 10)$$
Factor each group:
$$3c(-c + 2) - 5(c - 2)$$
Rewrite to match factors:
$$-3c(c - 2) - 5(c - 2)$$
Factor out $(c - 2)$:
$$(c - 2)(-3c - 5)$$
So numerator is:
$$c(c - 2)(-3c - 5)$$
4. **Factor the denominator:** Factor $5c^2 - 6c - 8$.
Find two numbers that multiply to $5 \times (-8) = -40$ and add to $-6$.
These are $4$ and $-10$ (no, sum is -6, 4 + (-10) = -6).
Rewrite:
$$5c^2 + 4c - 10c - 8 = (5c^2 + 4c) - (10c + 8)$$
Factor each group:
$$c(5c + 4) - 2(5c + 4)$$
Factor out $(5c + 4)$:
$$(5c + 4)(c - 2)$$
5. **Rewrite the entire fraction:**
$$\frac{c(c - 2)(-3c - 5)}{(5c + 4)(c - 2)}$$
6. **Cancel common factors:** $(c - 2)$ appears in numerator and denominator:
$$\frac{c\cancel{(c - 2)}(-3c - 5)}{(5c + 4)\cancel{(c - 2)}}$$
7. **Final simplified expression:**
$$\frac{c(-3c - 5)}{5c + 4} = \frac{-3c^2 - 5c}{5c + 4}$$
**Answer:** $$\frac{-3c^2 - 5c}{5c + 4}$$
Simplify Rational Expression 874B68
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.