# Homework Help: Rational expressions very simble, but hard for me

1. Apr 2, 2008

### physicsed

$$\frac{5x-5y-bx+by}{5x-5y+bx-by}$$

i can't cancel anything

i can't factor anything

2. Apr 2, 2008

### rock.freak667

5x-5y=5(x-y)
do the same with b

3. Apr 2, 2008

### physicsed

but the b's (x and y) doesn't cancel since they have two different signs

4. Apr 2, 2008

### Dick

-bx+by=(-b)(x-y). (x-y) IS a factor of both the numerator and the denominator.