Quadratic Remainder C63623
1. **State the problem:** We have a quadratic polynomial $$f(x) = x^2 + ax + b$$ and two conditions based on remainders when divided by linear factors:
- When divided by $$x+1$$, the remainder is 2, so $$f(-1) = 2$$.
- When divided by $$x-3$$, the remainder is -10, so $$f(3) = -10$$.
We need to find the values of $$a$$ and $$b$$.
2. **Write the equations from the conditions:**
From $$f(-1) = 2$$:
$$(-1)^2 + a(-1) + b = 2 \implies 1 - a + b = 2$$
Simplify:
$$-a + b = 1 \quad \text{(Equation 1)}$$
From $$f(3) = -10$$:
$$3^2 + 3a + b = -10 \implies 9 + 3a + b = -10$$
Simplify:
$$3a + b = -19 \quad \text{(Equation 2)}$$
3. **Solve the system of linear equations:**
Equations:
$$-a + b = 1$$
$$3a + b = -19$$
Subtract Equation 1 from Equation 2 to eliminate $$b$$:
$$ (3a + b) - (-a + b) = -19 - 1$$
$$3a + b + a - b = -20$$
$$4a = -20$$
$$a = -5$$
Substitute $$a = -5$$ into Equation 1:
$$-(-5) + b = 1$$
$$5 + b = 1$$
$$b = 1 - 5 = -4$$
4. **Final answer:**
$$a = -5, \quad b = -4$$
Thus, the quadratic polynomial is:
$$f(x) = x^2 - 5x - 4$$