Question 256863
I believe your question was:
{{{(-4a^-1*b^2*c^4)/(2b^7c)}}}
step 1 - reduce the front numbers to get
{{{-2a^-1*b^2*c^4)/(b^7c)}}}
step 2 - combine your variables using the division rule. WHen you divide like bases, subtract the exponents.
{{{-2a^-1*b^-5*c^3)}}}
step 3- change all exponents into positives if needed as
{{{-2*c^3/(a*b^5)}}}