Draw the structural formula for both of these alcohols: 2,3, 4-trimethyl, 3-heptanol
4-ethyl, 4-octanol

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explanation:

When naming organic compounds based on IUPAC; we take note of functional group, position of functional group.

In 2,3,4-trimethyl-3-heptanol, the functional group is hydroxyl group ( OH ). It is on position 3 (2,3,4-trimethyl-3-heptanol. Then we put it on the third carbon. Another functional group is methyl group, with three positions, 2, 3, and 4.

In 4-ethyl-4-octanol, the functional group is hydroxyl group ( OH ) which is in position 4 on the fourth carbon. Another functional group is ethyl group in position 4 on the fourth carbon. In this case, the functional groups that have same position, are put on that same carbon.