Final answer:
To get -3x^2 + 4x + 7 from 7x^2 - 5x + 1, you need to add 4x^2 - x + 8.
Step-by-step explanation:
To find what needs to be added to 7x2 - 5x + 1 to get -3x2 + 4x + 7, we need to perform addition and combine like terms with the same degree of x. Start by matching the terms with the same degree of x together:
(7x2 - 3x2) + ( -5x + 4x ) + 1 + 7
Combine the like terms:
4x2 - x + 8
Therefore, what needs to be added is 4x2 - x + 8.