to multiply them you have to first change them to rational exponents and then find the LCD, finally do what you have to do
(please consider the brace as the radical sign)
3{a2(2 is the exponent of a) • 4{a
=a2/3( 2/3 is the rational exponent) • a1/3
=a8/12 • a3/12
=12{a8 • 12{a3
=12{a11
i hope this was helpful!
