# Whats the difference between ez isomerism and cis and trans isomers? (they both seem to basically have the same rules so i don't get the difference)

They are the same, $\text{E- "-=" trans-}$ and $\text{Z- "-=" cis-}$. Except E-Z is used for more complex isomers.
Each 'corner' has something different, there is nothing to compare each other too. However, EZ notation uses the total atomic mass of each corner to decide upon E- or Z-. In this case, on the left hand side $C {H}_{3} C {H}_{2}$ has a greater mass than $C {H}_{3}$, on the right hand side, $C {H}_{2} O H$ has a greater mass than $C O H$. As the heaviest 'corner' on each side is on opposite sides, it is an E- isomer.