Question

giúp mình 2 bài dưới với ạ

Answer 1

bài 10

b) x³-5x-14=x(x²-5x-14)=x(x²+7x-2x-14)=x[(x²-2x)+(7x-14)]=x[x(x-2)+7(x-2)]=x(x-2)(x+7)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x-2=0\\x+7=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\\x=-7\end{matrix}\right.\)

Answer 2

Bài 10:

c: Ta có: \(x^3-5x^2-14x\)

\(=x\left(x^2-5x-14\right)\)

\(=x\left(x-7\right)\left(x+2\right)\)