Question

Answer 1

c: \(\Leftrightarrow\left(x^2+2\right)^2-2x\left(x^2+2\right)+x\left(x^2+2\right)-2x^2=0\)

\(\Leftrightarrow\left(x^2+2\right)\left(x^2+2-2x\right)+x\left(x^2+2-2x\right)=0\)

\(\Leftrightarrow\left(x^2-2x+2\right)\left(x^2+x+2\right)=0\)

=>PTVN

b: Đặt a=2017-x; b=2019-x

Theo đề, ta có: \(a^3+b^3-\left(a+b\right)^3=0\)

\(\Leftrightarrow\left(a+b\right)^3-3ab\left(a+b\right)-\left(a+b\right)^3=0\)

\(\Leftrightarrow\left[{}\begin{matrix}2017-x=0\\2019-x=0\\2x-4036=0\end{matrix}\right.\Leftrightarrow x\in\left\{2017;2018;2019\right\}\)