im having a problem to try to find the lcm of this expression as the if the lcm is (x-3) one of the fractions is left with a denominator plus the lcm

Hi, Bertu.

If I'm reading your question correctly, you are asking to find the lcm of the expression:

2 + 5x .

x - 3 (x - 3)^2

Do you see how the factor (x - 3) is duplicated? I tell my students that when that happens, choose the "higher one" as your lcm (what I mean by "higher one" is the factor with the higher exponent value). So the lcm of this expression is (x - 3)^2.

You didn't ask this, but just in case...

If the problem had asked you to simplify this expression, you would need to first rewrite it with equivalent fractions:

lcm is (x - 3)^2 ... so write both fractions with this denominator:

2 •
(x - 3) + 5x .

x - 3 • (x - 3) (x - 3)^2

The new numerator for the first fraction is now 2x - 6:

2x - 6 + 5x .

(x - 3)^2 (x - 3)^2

Combine the numerators:

2x - 6 + 5x .

(x - 3)^2

Then combine like terms:

7x - 6 .

(x - 3)^2

This is the original problem's expression simplified (just in case they ask)

Hope this helps you.