Tham khảo
`a) f(x)=5x^2-2x+5`
`+g(x)=5x^2-6x-\frac{1}{3}`
_____________________________
`f(x)+g(x)=10x^2-8x+\frac{14}{3}`
`b) f(x)=5x^2-2x+5`
`-g(x)=5x^2-6x-\frac{1}{3}`
_____________________________
`f(x)+g(x)=4x+\frac{16}{3}`
`c)` Cho `f(x)-g(x)=0`
`⇔4x+\frac{16}{3}=0`
`⇔4x=\frac{-16}{3}`
`⇒x=\frac{-4}{3}`
Vậy `x=\frac{-4}{3}` thì `f(x)-g(x)=0`
`\text{©CBT}`