(a) 2-Methylhex-1-eneCondensed: CH2=C(CH3)-CH2-CH2-CH2-CH3.Tip: Draw hex-1-ene, number from the double-bond end, put a CH3 on C2.(b) 4,4-Dimethylpent-2-yneCondensed: CH3-C≡C-C(CH3)2-CH3.Tip: Make pent-2-yne (triple between C2–C3); at C4 attach two CH3 groups.(c) 2-Methylhexa-1,5-dieneCondensed: CH2=C(CH3)-CH2-CH2-CH=CH2.Tip: Start with hexa-1,5-diene; add CH3 on C2.(d) 3-Ethyl-2,2-dimethylhept-3-eneCondensed: CH3-C(CH3)2-CH(C2H5)=CH-CH2-CH2-CH3.Tip: Hept-3-ene main chain; two CH3 on C2, an ethyl on C3.