9. Halla el común denominador de las fracciones. \( \frac{8}{9} \) y \( \frac{3}{99} \)

Determine whether the following statment is true or false. The graph of \( y=\frac{1}{7} g(x) \) is the graph of \( y=g(x) \) stretched by a factor of 7 . Choose the correct answer below. A. True, because the graph of the new function is obtained by adding 7 to each \( x \)-coordinate. Balse, because the graph of the new function is obtained by multiplying each \( y \)-coordinate of \( y=g(x) \) by \( \frac{1}{7}<1 \). C. True, because the graph of the new function is obtained by multiplying each \( y \)-coordinate of \( y=g(x) \) by 7 and \( 7>1 \). D. False, because the graph of the new function is obtained by adding 7 to each \( x \)-coordinate.

A 25 -year old woman burns \( 350-70 t \) cal/hr while walking on her treadmill. Her caloric intake from drinking Gatorade is \( 135 t \) calories during the \( t \) th hour. What is her net decrease in calories after walking for 4 hours?

Consider the number pattern below: \[ \frac{-3}{5} ; \frac{-6}{9} ; \frac{-9}{13} ; \ldots . \ldots \] Determine the next two terms of the number pattern. Determine the \( n^{\text {th }} \) term of the number pattern.

Determina il valore dell'espressione in notazione scientifica : \[ \left(1,2 \cdot 10^{3}-19 \cdot 10^{2}\right)^{2}:\left(0,07 \cdot 10^{3}\right) \cdot 0,03 \]

The postal service of a country charges \( \$ 0.36 \) postage for a letter weighing up to 1 ounce, plus \( \$ 0.26 \) for each additional ounce up to 5 ounces. Letters weighing more than 5 ounces do not qualify for these rates. \( C(x)=\left\{\begin{array}{ll}\$ \square & \text { if } 0<x \leq 1 \\ \text { (a) Write a piecewise-defined function } C \text { for the postage charged for a letter weighing } x \text { ounces. } \\ \$ \square & \text { if } 3<x \leq 4 \\ \$ \square & \text { if } 4<x \leq 5\end{array}\right. \)