ok first set it up as a fraction. so it would like this __(3.5*10__^{-6})

(5.0*10^{-2}) Divide 3.5/5= .7 then add the exponents which would -8

so your answer would be (.7*10^{-6}) but its not in scientific notation so it would actually be (7*10^{-5}) I got that answer by moving the decimal to the right once and decreasing the exponet by one.