How do write in simplest form given #-2/5+17/20#?

2 Answers
Oct 24, 2016

#9/20#

Explanation:

To do the simplification we require the denominators of the fractions to be the same.

To make the denominator of the first fraction 20, multiply numerator/denominator by 4, equivalent to multiplying by 1.

#-2/5xx4/4=-8/20#

We now have.

#-8/20+17/20#

Now we just add the numerators.

#rArr-8/20+17/20=(-8+17)/20=9/20#

Oct 27, 2016

#9/20#

Explanation:

#color(blue)("The structure of a fraction is:")#

#color(green)(("count")/("size indicator") " "color(brown)(vec("mathematical names"))" " ("numerator")/("denominator"))#

You can not 'directly' add or subtract counts unless the size indicators are the same.

#color(brown)("Multiply by 1 and you do not change the underlying value of ")##color(brown)("something. However, 1 comes in many forms.")#

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(blue)("Answering the question")#

Make all the size indicators (denominators) the same then subtract the counts (numerators).

#[ -2/5color(magenta)(xx1)]+17/20" "->" "[ -2/5color(magenta)(xx4/4)]+17/20#

#""-(2xx4)/(5xx4)" "+17/20" "->" "-8/20" "+17/20#

#color(white)(.)#

#" "(17-8)/20" " =" " 9/20 #