# Week 14

This past week in Pre Calculus 11 we started unit 7: Rational Expressions and Equations. Something I learned this week was how to simplify an expression. If the equation was $\frac{\left(x-3\right)\left(x+4\right)}{\left(x+4\right)\left(x+6\right)}$ both (x+4) on the top and bottom cancel out leaving $\frac{\left(x-3\right)}{\left(x+6\right)}$ . A non-permissible value means if that number was substituted in for a variable it would make the denominator a 0 which is not what we want so it can not be these values. Looking at the original equation $\frac{\left(x-3\right)\left(x+4\right)}{\left(x+4\right)\left(x+6\right)}$ (x+4) and (x+6) are on the bottom so their non-permissible value would be -4 and -6.