a: \(\Leftrightarrow\left(2x-5\right)^3=225-4\cdot100=125\)
=>2x-5=5
=>2x=10
hay x=5
b: \(\Leftrightarrow\left(x-2\right)\left(x-5\right)=0\)
hay \(x\in\left\{2;5\right\}\)
c: =>x-5-2x-7=-8
=>-x-12=-8
=>x+12=8
hay x=-4
\(\left(2x-5\right)^3=15^2-4.5^2\)
\(\Leftrightarrow\left(2x-5\right)^3=125\)
\(\Leftrightarrow2x-5=5\)
\(\Leftrightarrow x=5\)
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\(\left(x-2\right)\left(15-3x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2=0\\15-3x=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=5\end{matrix}\right.\)
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\(\left(x-5\right)-\left(2x+7\right)=-8\)
\(\Leftrightarrow x-5-2x-7=-8\)
\(\Leftrightarrow-x=4\)
\(\Leftrightarrow x=-4\)