Answer: -5x³ + x² + 4x + 8
Explanation
This is a polynomial expressions of third order.
The equation
(-4x³ + x² ) + (- x³ + 4x + 8)
Adding them together according to their order, we now have
( -4x³ + (-x³) + x² + 4x + 8 )
-4x³ - x³ + x² + 4x + 8
-5x³ + x² + 4x + 8