Write down the structural formulas and name the following alkanes according to the rational nomenclature

Write down the structural formulas and name the following alkanes according to the rational nomenclature: a) 2,3,4-trimethylpentane; b) 2,4-dimethyl-3-ethylpentane; c) 3,4,5-trimethyl-2-ethyl-4-isopropylhexane.

In order to write the formula of a substance, you need to look at the root of the last word, it determines the number of carbons in the chain, so in the formula 2,3,4-trimethylpentane, the penta root denotes the presence of five carbons in the chain, the numbers 2,3,4 indicate the location of the radicals in the formula, that is, at places 2,3 and 4 of carbons, methyl (CH3) radicals will stand.