\(\sqrt{4-5x}=12\) ĐK: \(x\le\dfrac{4}{5}\)
<=> \(4-5x=144\)
<=> \(x=-28\) (TM)
Giải:
\(\sqrt{4-5x}=12\)
\(\Leftrightarrow4-5x=144\)
\(\Leftrightarrow5x=4-144\)
\(\Leftrightarrow5x=-140\)
\(\Leftrightarrow x=-28\)
Vậy ...
ĐKXĐ:x\(\le\dfrac{4}{5}\)
\(\Leftrightarrow\)4-5x=144\(\Leftrightarrow5x=-140\Leftrightarrow x=-28\)(TMĐK)