Question

giải pt \(\sqrt{x-1}\) = 7

Answer 1

\(\Leftrightarrow x-1=49\)

hay x=50

Answer 2

\(ĐK:x\ge1\\ PT\Leftrightarrow x-1=49\Leftrightarrow x=50\left(tm\right)\)

Answer 3

\(\sqrt{x-1} = 7. Điều kiện: >= 1 \)

\(<=> (\sqrt{x-1})^{2} = (7)^{2} \)

\(<=> x-1=49 \)

\(<=> x=50 (t/m) \)