91Ó°ÊÓ

For exercises 43-58, (a) solve. (b) check. $$ \frac{9}{10} v+\frac{1}{3}=-\frac{22}{15} $$

For exercises \(35-86\), simplify. $$ \frac{x}{x-2}-\frac{4 x}{x^{2}-4} $$

For exercises 39-82, simplify. $$ \frac{5 b+15}{4 b+4} \div \frac{2 b+6}{7 b+7} $$

For exercises 77-86, find any values of the variable for which this expression is undefined. $$ \frac{5}{x^{2}+6} $$

If \(\$ 500\) is invested for 10 years and earns simple interest, find the annual simple interest rate needed to earn \(\$ 425\) in interest.