Question 835145
3 Over a+2  - 2 over a-1 the answer was a-7 over(a+2) (a-1)
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Enter it like this:
3/(a+2) - 2/(a-1) not with "over" "under" etc.
You can use 3 sets of braces { } to get
{{{3/(a+2) - 2/(a-1)}}}
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{{{3/(a+2) - 2/(a-1)}}}
To combine fractions, the denominators have to be the same.  You need a "common denominator."
The product of the DENs always works.  For this one, that's (a+2)*(a-1)
{{{3/(a+2) - 2/(a-1)}}}
= {{{3(a-1)/((a+2)*(a-1)) - 2(a+2)/((a+2)*(a-1))}}}
Now that the DENs are the same, you can combine the numerator terms.
= {{{(3a-3)/((a+2)*(a-1)) - (2a-4)/((a+2)*(a-1))}}}
= {{{(a-7)/((a+2)*(a-1))}}}