Question

Giai chi tiết PT sau: x² - 4 + x + 2 = 0

Answer 1

\(x^2-4+x+2=0\)

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

\(\Leftrightarrow\left(x+2\right)\left(x-1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+2=0\\x-1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=1\end{matrix}\right.\)

Answer 2

x²-4+x+2

=(x²-2²)+x+2)

=(x-2)*(x+2)+(x+2)

=(x+2)*(x-2+1)

=(x+2)*(x-1)

Answer 3

x²-2+x=0

x²+x-2=0

x²+2x-x-2=0

x(x+2)-(x+2)=0

(x+2)(x-1)=0

\(\left\{{}\begin{matrix}x+2=0\\x-1=0\end{matrix}\right.\)

\(\left\{{}\begin{matrix}-2\\1\end{matrix}\right.\)