Problem
Simplify: \[ \left(3 x^{2}+2 x-8\right)-\left(-x^{2}+6 x+4\right) \] A. \( 2 x^{2}+8 x-4 \) B. \( 2 x^{2}+8 x-12 \) C. \( 4 x^{2}+8 x-4 \) D. \( 4 x^{2}-4 x-12 \)
Solution
Step 1 ：\( (3 x^{2}+2 x-8) - (-x^{2}+6 x+4) \)
Step 2 ：\( 3x^{2} + 2x - 8 + x^{2} - 6x - 4 \)
Step 3 ：\( 4x^{2} - 4x - 12 \)
