\(\Leftrightarrow\sqrt{1-x}+2\sqrt{1-x}=12\)
\(\Leftrightarrow3\sqrt{1-x}=12\)
=>1-x=16
hay x=-15
\(\Leftrightarrow\left(\sqrt{1-x}+\sqrt{4-4x}\right)^2=12^2\)
\(\Leftrightarrow1-x+4-4x+2\sqrt{\left(1-x\right)\left(4-4x\right)}=144\)
\(\Leftrightarrow-5x+5+2\sqrt{\left(1-x\right)\left(4-4x\right)}=144\)
\(\Leftrightarrow\left(2\sqrt{\left(1-x\right)\left(4-4x\right)}\right)^2=\left(139+5x\right)^2\)
\(\Leftrightarrow4\left(4-4x-4x+4x^2\right)=19321+1390x+25x^2\)
\(\Leftrightarrow16x^2-32x+16=19321+1390x+25x^2\)
\(\Leftrightarrow9x^2+1422x+19305=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-14,7\\x=-143,2\end{matrix}\right.\)
