a) A box has 12 bulbs, 3 of which are defective. If two bulbs are to be selected at random without replacement, then what. is the probability that both bulbs are defective? b) There are two telephone lines \( A \) and \( B \). Line \( A \) is engaged \( 50 \% \) of the time and line B is engaged \( 60 \% \) of the time. Both lines are engaged \( 30 \% \) of the time. Calculate the probability that only one line is engaged.

5. Amira buys cookies and onions at the store. - She pays a total of \( \$ 51.40 \). - She pays a total of \( \$ 6.18 \) for the cookies. - She buys 7 bags of onions that each cost the same amount. How much does each bag of onions cost?

\( \$ 7 \) is what percent of \( \$ 10 \) ? Write your answer using a percent sign (\%). For example, \( 0.5 \%, 12.7 \% \), or \( 56 \% \).

Solve \( r^{4}-41 r^{2}+400=0 \) List them separated by commas, for example: \( \frac{2}{3}, \frac{5}{2}, \sqrt{5},-\sqrt{5} \) type \( 2 / 3,5 / 2 \), sqrt(5),-sqrt(5)"

\( 1< \) For the function, \( f(x)=-2 x+5 \), complete parts a through \( c \). c) \( \frac{f(x+h)-f(x)}{h}=\square \) (Simplify your answer.)

e \( -\frac{1}{3} x+10=1 \)