Question 173556: Adding/Subtracting rational expressions
y^2/y - 4 - 4/y - 4
Answer by nycsub_teacher(90)   (Show Source):
You can put this solution on YOUR website! I assume you meant to type this
[y^2/(y - 4)] - [4/(y - 4)]
Treat this like you would a regular fraction.
Notice that the denominator is the same for both fractions.
In that case, we keep the denominator (y - 4) and subtract the numerators.
Doing that, this is what we get:
(y^2 - 4)/(y - 4)
Now, what can we do with the numerator (y^2 - 4)? What does it look like?
We can say that (y^2 - 4) is the difference of two perfect squares and so it can and must be factored.
(y^2 - 4) factors out to be (y - 2) (y + 2)
Final answer:
[(y - 2)(y + 2)]/(y - 4)
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