1) A(x) + B(x) = (1 + 2x^2 – 5x^4) + (3 – 7x^2 + x^3)
= 1 + 2x^2 – 5x^4 + 3 – 7x^2 + $\frac{1}{2}$ x^3
= (1 + 3) + (2x^2 - 7x^2) – 5x^4 + $\frac{1}{2}$ x^3
= 4 + (-5)x^2 + 5x^4 + $\frac{1}{2}$ x^3
2) A(x) - B(x) = (1 + 2x^2 – 5x^4) - (3 – 7x^2 + x^3)
= 1 + 2x^2 – 5x^4 - 3 + 7x^2 - $\frac{1}{2}$ x^3
= (1 - 3) + (2x^2 + 7x^2) - 5x^4 - $\frac{1}{2}$ x^3
= -2 + 9x^2 - 5x^4 - $\frac{1}{2}$ x^3
3) B(x) - A(x) = (3 – 7x^2 + x^3) - (1 + 2x^2 – 5x^4)
= 3 – 7x^2 + x^3 - 1 - 2x^2 + 5x^4
= (3 - 1) + (– 7x^2 - 2x^2) + x^3 + 5x^4
= 2 + -9x^2 + x^3 + 5x^4
#ht
*Xin câu trả lời hay nhất
