Give the IUPAC name for the following alkane.
`(a)` `CH_(3)-underset(CH_(2))underset(|)underset(CH_(2))underset(|)(CH)-CH_(2)-CH_(2)-underset(CH_(2))underset(|)underset(CH_(2))underset(|)(CH)-CH_(3)`
`(b)` `CH_(3)-underset(CH_(3))underset(|)(CH)-underset(CH_(3))underset(|)(CH)-underset(CH_(3))underset(|)underset(CH_(2))underset(|)(CH)-CH_(2)-CH_(2)-CH_(2)-CH_(3)`

Explanation

`(a)` `underset((3,6,"dimethyl octene"))(CH_(3)-underset(CH_(2))underset(|8)underset(CH_(2))underset(|7)overset(6)(CH)-overset(5)(CH_(2)))-overset(4)(CH_(2))-underset(CH_(2))underset(|1)underset(CH_(2))underset(|2)overset(3)(CH)-CH_(3)`
`(b)` `underset((4,"ethyl",2,3-"dimethyl octene"))(overset(1)(CH_(3))-underset(CH_(3))underset(|)overset(2)(CH)-underset(CH_(3))underset(|)overset(3)(CH)-underset(CH_(3))underset(|)underset(CH_(2))underset(|)overset(4)(CH)-Coverset(5)(H_(2))-Coverset(6)(H_(2)))-Coverset(7)(H_(2))-Coverset(8)(H_(3))`