## week 14 precalc 11

This week we started with unit 7 of rational expressions.  We started with the basics of non-permissible values which are the values of x that make the denominator equal zero.  By simplifying rational expressions we can find x which are the non-permissible values.

In 7.2 we learned how to multiply and divide rational expressions by cross cancelling when simplified.

$\frac{3x}{2(x-3)} \frac{8(x-3)}{9x^2}$

$\frac{4}{3x}$

x cannot equal 3 and 0.

Then we learned how to add and subtract rational expressions with monomial denominators.  by finding the common denominator we can expand and reduce to end up with one simplified fraction.

$\frac{2x-3}{x} + \frac{x-1}{3x}$
$\frac{6x-9}{3x} + \frac{x-1}{3x}$
$\frac{7x-10}{3x}$