a) \(\dfrac{2}{5}:x-\dfrac{1}{5}=-\dfrac{4}{5}\)
\(\dfrac{2}{5}:x=\left(-\dfrac{4}{5}\right)+\dfrac{1}{5}\)
\(\dfrac{2}{5}:x=\left(-\dfrac{3}{5}\right)\)
\(x=\dfrac{2}{5}\cdot\left(-\dfrac{5}{3}\right)\)
\(x=-\dfrac{2}{3}\)
b) \(\left(x+3\right)^2=17-1\)
\(\left(x+3\right)^2=16\)
\(\left(x+3\right)^2=4^2\)
`=>`\(\left[{}\begin{matrix}x+3=4\\x+3=-4\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}x=1\\x=-7\end{matrix}\right.\)
c) \(-\dfrac{2}{3}\cdot x+2=-\dfrac{1}{3}\)
\(-\dfrac{2}{3}\cdot x=-\dfrac{1}{3}-2\)
\(-\dfrac{2}{3}\cdot x=-\dfrac{7}{3}\)
\(x=\left(-\dfrac{7}{3}\right)\cdot\left(-\dfrac{3}{2}\right)\)
\(x=\dfrac{7}{2}\)
d) \(5^{x+2}=25\cdot100:4\)
\(5^{x+2}=625\)
\(5^{x+2}=5^4\)
`=>x+2=4`
`x=4-2`
`=>x=2`
e) \(x^2\cdot x^1=54:2\)
\(x^3=27\)
\(x^3=3^3\)
`=>x=3`
