16. What is the correct name of HBr ?

\( 1,4,9,16, \ldots= \) general \( 100,50,25,12.5, \ldots= \) geometric \( 1,8,27,64 \ldots= \)

How else can the ratio \( 4 / 5 \) be written?

A) \( \frac{1}{4}+\frac{2}{6}= \)

i) If \( x+y=\begin{array}{ll}5 & 2 \\ 0 & 9\end{array} \) and \( x-y=\begin{array}{cc}3 & 6 \\ 0 & -1\end{array} \) then calculate \( x \) and \( y \).

A company distributes college logo sweatshirts and sells them for \( \$ 45 \) each. The total cost function is linear, and the total cost for 70 sweatshirts is \( \$ 4136 \), whereas the total cost for 220 sweatshirts is \( \$ 5785 \). (a) Write the equation for the revenue function \( R(x) \). \( R(x)=\square \) (b) Write the equation for the total cost function \( C(x) \). \( C(x)=\square \) (c) Find the break-even quantity. \( x=\square \)