How do you evaluate #(-1/5)+7/4#?

1 Answer
Nov 29, 2016

#31/20#

Explanation:

#(-1/5)+7/4=7/4-1/5#

You cannot add or subtract until you have same denominators, so you can start by unifying the denominator

#7/4-1/5=(7*5)/(4*5)-(1*4)/(5*4)=35/20-4/20#

When you multiply by #5/5# and #4/4# you actually do not change the value of the expression, because #5/5=1# and #4/4=1# so you are multiplying by #1# which does not affect the expression

Now after you have like denominators, you can subtract

#35/20-4/20=31/20#