Answer:
They most have common denominators.
Step-by-step explanation:
Let the following two rational expressions:
[tex]\frac{p}{a} , \frac{q}{b}[/tex]
where p,a,q, b are integers, a and b the denominators are not 0, i.e. [tex]a,b\neq 0[/tex]
We can add rational expressions only if their denominator is same.
That is why we find LCD to be [tex]ab[/tex].
Then,
[tex]\frac{p}{a} +\frac{q}{b} =\frac{pb+qa}{ab}[/tex]
Let the following two rational expressions:
[tex]\frac{p}{a} , \frac{q}{b}[/tex]
where p,a,q, b are integers, a and b the denominators are not 0, i.e. [tex]a,b\neq 0[/tex]
We can add rational expressions only if their denominator is same.
That is why we find LCD to be [tex]ab[/tex].
Then,
[tex]\frac{p}{a} +\frac{q}{b} =\frac{pb+qa}{ab}[/tex]
So, the correct answer is the last option that we can sum rational expressions if they have common denominator.
