[tex] a) \: {3}^{19} \times {3}^{17} = {3}^{19 + 17} = {3}^{36} [/tex]
[tex]b ) \: {3}^{19} \div {3}^{17} = {3}^{19 - 17} = {3}^{2} = 9[/tex]
[tex]f )\: {2}^{100} \times {2}^{99} \div {2}^{97} = ( {2}^{100 + 99} ) \ \div {2}^{97} = {2}^{199} \div {2}^{97} = {2}^{199 - 97} = {2}^{102} [/tex]