Let's simplify the expression step by step:
Given expression:
\[ (8x^2 - 7x + 3) - (3x - 9) + (-5x^2 + 2x) \]
- Distribute the negative sign in the second term:
\[ (8x^2 - 7x + 3) - 3x + 9 + (-5x^2 + 2x) \]
- Combine the constant terms and like terms. Start with the \(x^2\) terms:
\[ 8x^2 - 5x^2 = 3x^2 \]
Next, combine the \(x\) terms:
\[ -7x - 3x + 2x = -8x \]
And finally, combine the constant terms:
\[ 3 + 9 = 12 \]
- Putting it all together, you get:
\[ 3x^2 - 8x + 12 \]
Thus, the simplified expression is:
\[ \boxed{3x^2 - 8x + 12} \]