1. **State the problem:** Simplify the expression $$\frac{2y + 1}{2y^2 + y - 1} + \frac{3}{2 - 3y + 2y^2}$$.
2. **Rewrite the denominators in a standard polynomial form:**
- First denominator: $$2y^2 + y - 1$$
- Second denominator: $$2 - 3y + 2y^2$$ can be rewritten as $$2y^2 - 3y + 2$$.
3. **Factor the denominators:**
- Factor $$2y^2 + y - 1$$:
Find two numbers that multiply to $$2 \times (-1) = -2$$ and add to $$1$$. These are $$2$$ and $$-1$$.
So,
$$2y^2 + y - 1 = 2y^2 + 2y - y - 1 = 2y(y + 1) -1(y + 1) = (2y - 1)(y + 1)$$.
- Factor $$2y^2 - 3y + 2$$:
Find two numbers that multiply to $$2 \times 2 = 4$$ and add to $$-3$$. These are $$-1$$ and $$-2$$.
So,
$$2y^2 - 3y + 2 = 2y^2 - 2y - y + 2 = 2y(y - 1) -1(y - 2)$$ but this does not factor nicely this way.
Let's try the quadratic formula or check for factorization:
The discriminant is $$(-3)^2 - 4 \times 2 \times 2 = 9 - 16 = -7$$, which is negative, so it does not factor over the reals.
4. **Rewrite the expression with factored denominators where possible:**
$$\frac{2y + 1}{(2y - 1)(y + 1)} + \frac{3}{2y^2 - 3y + 2}$$.
5. **Find a common denominator:**
Since the second denominator does not factor nicely, the common denominator is $$ (2y - 1)(y + 1)(2y^2 - 3y + 2) $$.
6. **Rewrite each fraction with the common denominator:**
- First fraction numerator multiplied by $$2y^2 - 3y + 2$$:
$$ (2y + 1)(2y^2 - 3y + 2) $$
- Second fraction numerator multiplied by $$ (2y - 1)(y + 1) $$:
$$ 3(2y - 1)(y + 1) $$
7. **Expand the numerators:**
- Expand $$ (2y + 1)(2y^2 - 3y + 2) $$:
$$2y \times 2y^2 = 4y^3$$
$$2y \times (-3y) = -6y^2$$
$$2y \times 2 = 4y$$
$$1 \times 2y^2 = 2y^2$$
$$1 \times (-3y) = -3y$$
$$1 \times 2 = 2$$
Sum: $$4y^3 - 6y^2 + 4y + 2y^2 - 3y + 2 = 4y^3 - 4y^2 + y + 2$$
- Expand $$3(2y - 1)(y + 1)$$:
First expand $$(2y - 1)(y + 1)$$:
$$2y \times y = 2y^2$$
$$2y \times 1 = 2y$$
$$-1 \times y = -y$$
$$-1 \times 1 = -1$$
Sum: $$2y^2 + 2y - y - 1 = 2y^2 + y - 1$$
Multiply by 3:
$$3(2y^2 + y - 1) = 6y^2 + 3y - 3$$
8. **Add the numerators:**
$$4y^3 - 4y^2 + y + 2 + 6y^2 + 3y - 3 = 4y^3 + 2y^2 + 4y - 1$$
9. **Final expression:**
$$\frac{4y^3 + 2y^2 + 4y - 1}{(2y - 1)(y + 1)(2y^2 - 3y + 2)}$$
10. **Summary:** The sum of the two rational expressions simplifies to $$\frac{4y^3 + 2y^2 + 4y - 1}{(2y - 1)(y + 1)(2y^2 - 3y + 2)}$$.
This is the simplified form since the denominator cannot be factored further over the reals.
Rational Expression Addition
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.