If one of the roots of the equation `x^(2) + ax - 6 = 0` is 1, then what is (a-6) equal to ?

Options

A. -1
B. 1
C. 2
D. -2

Explanation

To solve the problem, we need to find the value of \( a - 6 \) given that one of the roots of the quadratic equation \( x^2 + ax - 6 = 0 \) is 1.

### Step-by-Step Solution:

1. **Substitute the root into the equation**: Since 1 is a root of the equation, we can substitute \( x = 1 \) into the equation.
\[ 1^2 + a(1) - 6 = 0 \]

2. **Simplify the equation**: Calculate \( 1^2 \) and substitute it into the equation.
\[ 1 + a - 6 = 0 \]

3. **Combine like terms**: Simplify the left-hand side.
\[ a - 5 = 0 \]

4. **Solve for \( a \)**: Rearranging gives us the value of \( a \).
\[ a = 5 \]

5. **Find \( a - 6 \)**: Now, we need to find \( a - 6 \).
\[ a - 6 = 5 - 6 = -1 \]

### Final Answer:
\[ a - 6 = -1 \]