Question

Bài 1: Tìm x, biết

Câu\(1.\left(x-1\right)^2=4\)

Câu \(2.\left(x+1\right).\left(x-1\right)\le0\)

 

Answer 1

\(\left(x-1\right)^2=4\)

\(\Rightarrow\orbr{\begin{cases}x-1=-2\\x-1=2\end{cases}\Rightarrow\orbr{\begin{cases}x=-1\\x=3\end{cases}}}\)

\(\left(x+1\right)\left(x-1\right)\le0\)

\(\Rightarrow x^2-1\le0\)

\(\Rightarrow x^2\le1\)

\(\Rightarrow x\le1\)

Answer 2

\(\left(x-1\right)^2=4\)

\(\Rightarrow\left(x-1\right)^2=2^2\)

\(\Rightarrow x-1=2\)

\(\Rightarrow x=2+1\)

\(\Rightarrow x=3\)