A(x)+B(x)=(4x²−3x²−7x+5)+(−4x³+3x²+4x−11)
=4x²−3x²−7x+5−4x³+3x²+4x−11
=−4x³+(4x²−3x²+3x²)−(7x−4x)+(5−11)
=−4x³+4x²−3x−6
Vậy A(x)+B(x)
=(4x²−3x²−7x+5)−(−4x³+3x²+4x−11)
=4x²−3x2−7x+5+4x³−3x²−4x+11
=4x³+(4x²−3x²−3x²)−(7x+4x)+(5+11)
=4x³−2x²−11x+16
Vậy A(x)−B(x)
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