How do you evaluate #-4\frac { 1} { 5} - 7\frac { 1} { 2}#?

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Answer 1 · 2017-09-25T12:52:52

#-11 7/10# or #-11.7#

First, we convert the mixed numbers to improper fractions:

#-4 1/5-7 1/2 -> -21/5-15/2#

Then we find the LCD (Least Common Denominator) which is #2*5=10#

Then we adjust the fractions:
#-(21*2)/10-(15*5)/10#

Now we combine the fractions and position them:
#(-2*21-5*15)/10#

#-2*21=-42#

#5*15=75#

#-42-75=-117#

The fraction will then be #(-117)/10# which is the same as #- 117/10#.

Now we convert it back to a mixed number:
#-11 7/10#
or decimal:
#-11.7#