[tex]2x^{3}+6=34[/tex]
To solve any equation you have to leave the variables in a side and all the numbers on the other, we can do that by subtracting 6 from each sides.
[tex]2x^{3}+6-6=34-6\\2x^{3}=28[/tex]
Now, divide the whole equation by 2.
[tex]2x^{3}=28\\\frac{2x^{3}}{2}=\frac{28}{2} \\\\x^{3}=14[/tex]
Getting simple here. Now, take the cube root for each side.
[tex]x^{3}=14\\\sqrt[3]{x^{3}}=\sqrt[3]{14} \\x=\sqrt[3]{14}[/tex]
So that's it!
[tex]x=\sqrt[3]{14} \\x=2.41014226[/tex]
ANOTHER WAY BY USING THE LOGARITHM RULES:
You can take it as informative or alternative way of solving it, the one explained above is way easier.
[tex]2x^{3}+6=34\\2x^{3}=28\\x^{3}=14\\ln(x^{3})=ln(14)\\3ln(x)=ln(14)\\ln(x)=\frac{ln(14)}{3} \\e^{ln(x)}=e^{\frac{ln(14)}{3} }\\\\x=e^{\frac{ln(14)}{3} = 2.410142264}[/tex]