\(\left(7x-12\right)^2=2^5.5^2+200\)
\(\left(7x-12\right)^2=25.32+200\)
\(\left(7x-12\right)^2=800+200\)
\(\left(7x-12\right)^2=1000=\left(10\sqrt{10}\right)^2\)
\(\Leftrightarrow\left[{}\begin{matrix}7x-12=10\sqrt{10}\\7x-12=-10\sqrt{10}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{10\sqrt{10}+12}{7}\\x=\dfrac{12-10\sqrt{10}}{7}\end{matrix}\right.\)
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