Question 549760
We just need to add the heights of the two bookcases:
Let's first change both fractions to improper fractions:
14 1/2={{{(14*2+1)/2=29/2}}}
8 3/4={{{(8*4+3)/4=35/4}}}

So adding these together we have:
{{{(29/2)+(35/4)}}}
We need to get a common denominator (which is 4)
{{{(58/4)+(35/4)=93/4}}}

We can now change this to a mixed fraction again(though improper is still correct, just depending on the question and teacher).

93/4    --- we know that 4 goes into 93 23 times.  
Now 23*4=92 (so we have 1/4 left over)

So(93/4)=23 1/4

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Hopefully this helps!
Romans 5:8