Question

If one root of the quadratic equation \( y^2 + 3y - 18 = 0 \) is -6, then its other root is:

• A. \( 3 \)
• B. \( -3 \)
• C. \( 6 \)
• D. \( 5 \)

Hint:

For a quadratic equation \( ax^2 + bx + c = 0 \): \[ \text{Sum of roots} = -\frac{b}{a}, \quad \text{Product of roots} = \frac{c}{a}. \]

Answer 1

The Correct Option is A

Using the sum of roots:
\[ \alpha + \beta = -\frac{b}{a}. \] Given \( a = 1, b = 3, c = -18 \): \[ \alpha + \beta = -\frac{3}{1} = -3. \] One root is \( -6 \), so: \[ -6 + \beta = -3 \Rightarrow \beta = 3. \]