Bài 2:
a: \(f\left(x\right)=x^4+3x^2-5x+6\)
\(g\left(x\right)=x^4+2x^2-2x+6\)
\(H\left(x\right)=f\left(x\right)-g\left(x\right)=x^4+3x^2-5x+6-x^4-2x^2+2x-6\)
\(=x^2-3x\)
b: \(h\left(-\dfrac{1}{3}\right)=\dfrac{1}{9}+1=\dfrac{10}{9}\)
c: Đặt H(x)=0
=>x(x-3)=0
=>x=0 hoặc x=3