If the sum of `(8x^(2)-6x+9)" and "(-10x^(2)-8x-9)` is subtracted from `-3`, then find the coefficient of x.

Answer

To solve the problem step by step, we will follow these instructions:

1. **Identify the expressions to sum**: We have two expressions:
- \( 8x^2 - 6x + 9 \)
- \( -10x^2 - 8x - 9 \)

2. **Find the sum of the two expressions**:
\[ (8x^2 - 6x + 9) + (-10x^2 - 8x - 9) \]
To combine these, we will group like terms:
- Combine \( x^2 \) terms: \( 8x^2 - 10x^2 = -2x^2 \)
- Combine \( x \) terms: \( -6x - 8x = -14x \)
- Combine constant terms: \( 9 - 9 = 0 \)

So, the sum is:
\[ -2x^2 - 14x + 0 = -2x^2 - 14x \]

3. **Subtract the sum from -3**:
We need to subtract the result from -3:
\[ -3 - (-2x^2 - 14x) \]
This simplifies to:
\[ -3 + 2x^2 + 14x \]
Rearranging gives:
\[ 2x^2 + 14x - 3 \]

4. **Identify the coefficient of x**:
In the expression \( 2x^2 + 14x - 3 \), the coefficient of \( x \) is \( 14 \).

Thus, the coefficient of \( x \) is **14**.