Question

Tìm x:

a) (x-19).(x+21)=0

b)(53-x).(41+x)=0

Answer 1

\(a.\)

\(\left(x-19\right)\left(x+21\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-19=0\\x+21=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=19\\x=-21\end{matrix}\right.\)

\(S=\left\{19,-21\right\}\)

\(b.\)

\(\left(53-x\right)\left(41+x\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}53-x=0\\41+x=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=53\\x=-41\end{matrix}\right.\)

\(S=\left\{53,-41\right\}\)

Answer 2

Tìm x:

a) (x-19).(x+21)=0

<=>\(\left\{{}\begin{matrix}x-19=0< =>x=19\\x+21=0< =>x=-21\end{matrix}\right.\)

Vậy pt trên có tập nghiệm là: S={19;-21}

b)(53-x).(41+x)=0

<=>\(\left\{{}\begin{matrix}53-x=0< =>x=53\\41+x=0< =>x=-41\end{matrix}\right.\)

Vậy pt trên có tập nghiệm là S={53;-41}

Answer 3

a) x là 19 hoặc -21

b) x là 53 hoặc-41

cho tớ tim nhá

Answer 4

a) Ta có: (x-19)(x+21)=0

\(\Leftrightarrow\left[{}\begin{matrix}x-19=0\\x+21=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=19\\x=-21\end{matrix}\right.\)

Vậy: \(x\in\left\{19;-21\right\}\)

b) Ta có: (53-x)(41+x)=0

\(\Leftrightarrow\left[{}\begin{matrix}53-x=0\\41+x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=53\\x=-41\end{matrix}\right.\)

Vậy: \(x\in\left\{53;-41\right\}\)