How do you simplify #\frac { m - 4} { 12} - \frac { 10m } { 25}#?

1 Answer
Oct 1, 2017

#=(-19m-20)/60#

Explanation:

In order to add or subtract fractions you must have a common denominator:

#12 and 25# have no common factors,

The #LCD = 12 xx25 = 300#

Multiply each fraction by the 'missing' factor:

#(m-4)/12 xx25/25 -(10m)/25 xx12/12#

#=(25(m-4)-120m)/300#

# =(25m-100-120m)/300#

#=(-95m-100)/300" "larr# factorise the numerator

#=(cancel5(-19m-20))/cancel300^60" "larr# simplify

#=(-19m-20)/60#