Question

căn x^-4=x-2

tìm x

Answer 1

tham khảo:

Answer 2

ĐK: x≥2

\(\sqrt{x^2-4}=x-2\)

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

\(\Leftrightarrow4x=8\)

\(\Leftrightarrow x=2\left(tm\right)\)

Answer 3

Ta có: \(\sqrt{x^2-4}=x-2\)

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

\(\Leftrightarrow-4x=-8\)

hay x=2