I do npot understand how to do this problem, please help:

4y/y^2-y/y-3

Maybe because it's not yet a problem. You have posted an expression. What do you want to do with it?

Proofread you question before posting, pleeze.

Add and simplify

4y/y^2-9 + y/y-3

To simplify the expression (4y/y^2) - (y/y - 3), we need to find a common denominator for the fractions.

First, let's simplify each fraction individually:

1. 4y/y^2:
Since both the numerator and denominator have a common factor of y, we can cancel it out, leaving us with 4/y.

2. y/y - 3:
As we have a single term in the numerator, we can rewrite it as 1 * y, which results in y/y.
Now, let's find the common denominator for both fractions. In this case, the common denominator is y.

Now, rewriting each fraction with the common denominator:

1. 4/y becomes (4/y) * (y/y) which gives us 4y/y^2.
2. y/y - 3 becomes (1 * y)/y - 3. Simplifying further, we have y/y - 3/y, which gives us y/y - 3/y.

Combining the two fractions, we have:
(4y/y^2) - (y/y) + (3/y)

To subtract the fractions, we need to have a common denominator:

1. Since y^2 is already the denominator in the first fraction, we don't need to make any changes.
2. For the second fraction, y/y already has a common denominator. However, we need to manipulate the third fraction, (3/y), to have the same denominator as the first two fractions, which is y^2. To do this, we multiply both the numerator and denominator by y, resulting in (3y/y^2).

Now that all three fractions have a common denominator, we can combine them:

(4y - y + 3y)/(y^2)

Simplifying the numerator:

(4y - y + 3y) = 6y

So the final simplified expression is:

6y/(y^2)