## College Algebra 7th Edition

(a) Yes, these expressions are equal because: $\displaystyle \frac{3+a}{3}=\frac{3}{3}+\frac{a}{3}=1+\frac{a}{3}$ (b) No, denominators do not "add", i.e. $\frac{1}{a}+\frac{1}{b}\ne\frac{1}{a+b}$.