91Ó°ÊÓ

What is the area of the region described by the system of linear inequalities \(x \leq 3, y \leq 1,\) and \(x+y \geq 0 ?\)

Use the table below, which gives the percents of people in the contiguous United States living within 50 miles of a coastal shoreline and those living further inland. $$ \begin{array}{|l|c|c|} \hline \text { Qummoninititicustics } & \text { 1940 } & \text { 1997 } \\ \hline \begin{array}{l} \text { Living within 50 miles } \\ \text { of a coastal shoreline } \end{array} & 46 \% & 53 \% \\ \hline \text { Living farther inland } & 54 \% & 47 \% \\ \hline \end{array} $$ For each location, write a linear model to represent the percent at time \(t\) where \(t\) represents the number of years since 1940

You do 4 loads of laundry each week at a launderette where each load costs \(\$ 1.25 .\) You could buy a washing machine that costs \(\$ 400 .\) Washing 4 loads at home will cost about \(\$ 1\) per week for electricity. How many loads of laundry must you do in order for the costs to be equal?

A gold and copper bracelet weighs 238 grams. The volume of the bracelet is 15 cubic centimeters. Gold weighs 19.3 grams per cubic centimeter, and copper weighs 9 grams per cubic centimeter. How many grams of copper are mixed with the gold?

Explain why the system of inequalities has no solution. $$\begin{array}{l} 2 x-y>4 \\ y>2 x-2 \end{array}$$

It took 3 hours for a plane, flying against the wind, to travel 900 miles from Alabama to Minnesota. The "ground speed" of the plane is 300 miles per hour. On the return trip, the flight took only 2 hours with a ground speed of 450 miles per hour. During both flights the speed and the direction of the wind were the same. The plane's speed decreases or increases because of the wind as the verbal model below shows. Speed in still air \(]-[\text { Wind speed }]=\) Ground speed against wind Speed in still air \(+\text { Wind speed }]=\) Ground speed with wind Solve the linear system.

Evaluate the exponential expression. \((x+y)^{2}\) when \(x=5\) and \(y=2\)

Decide whether the graphs of the two equations are $$ y=4 x+3 ; 2 y-8 x=-3 $$