# How do you subtract 9/( y + 1) - 3/ ( 4y + 4)?

Nov 25, 2017

In order to subtract, they need to have the same base, so you need to multiply the sides with the opposite’s base

$\left(\frac{9}{y + 1}\right) \cdot \left(4 y + 4\right)$ -

(3/(4y+4))*(y+1))

=

$\frac{36 y + 36}{\left(y + 1\right) \left(4 y + 4\right)} - \frac{3 y + 3}{\left(y + 1\right) \left(4 y + 4\right)}$

Now you can subtract since they have the same bases

$\frac{33 y - 33}{\left(y + 1\right) \left(4 y + 4\right)}$