a, \(CH_2=CH-CH_2-CH_3\): But - 1 - en
\(CH_3-CH=CH-CH_3\): But - 2 - en
b, \(CH_2=CH-CH_2-CH_2-CH_3\): Pent - 1 - en
\(CH_3-CH=CH-CH_2-CH_3\): Pent - 2 - en
\(CH_2=C\left(CH_3\right)-CH_2-CH_3\): 2 - metylbut - 1 - en
\(CH_3-C\left(CH_3\right)=CH-CH_3\): 2 - metylbut - 2 - en
\(CH_2=CH-CH\left(CH_3\right)-CH_3\): 3 - metylbut - 1 - en