What should be added to x4+2x²-7 to obtain 4x4 -3x³+x²+2?

To obtain 4x^4 - 3x^3 + x^2 + 2 from x^4 + 2x^2 - 7, you need to add the following:

1. Subtract x^4 from both sides to balance the equation. This gives you 3x^4 - 3x^3 - x^2 + 9.

2. Add 3x^4 to the equation. This gives you 3x^4 + x^4 + 2x^2 - 7.

3. Subtract 2x^2 from both sides to balance the equation. This gives you 3x^4 - 3x^3 - x^2 + 9.

4. Finally, add 9 to the equation to get 4x^4 - 3x^3 + x^2 + 2.

So, you need to add 3x^4 - 3x^3 - x^2 + 9 to x^4 + 2x^2 - 7 to obtain 4x^4 - 3x^3 + x^2 + 2.