A(x) = 4x3 + 3x2 - 5x + 2
B(x) = -x3 + x2 + 4x -1
A(x) + B(x) : (3x2 + 4x3 - 5x + 2) + (x2 - x3 + 4x - 1)
=> 3x2 + 4x3 - 5x + 2 + x2 - x3 + 4x - 1
=> 3x3 + 4x2 - x + 1
Vậy A(x) + B(x) = 3x3 + 4x2 - x + 1
A(x) - B(x) : (3x2 + 4x3 - 5x + 2) - (x2 - x3 + 4x - 1)
=> 3x2 + 4x3 - 5x + 2 - x2 + x3 - 4x + 1
=> 5x3 + 2x2 - 9x + 3
Vậy A(x) - B(x) = 5x3 + 2x2 - 9x + 3