91Ó°ÊÓ

Solve by graphing. $$\begin{aligned} &3 x-y=3\\\ &2 x+y=2 \end{aligned}$$ (THE GRAPH CANNOT COPY)

The employees of a hardware store ordered lunch from a local delicatessen. The lunch consisted of 4 turkey sandwiches and 7 orders of french fries, for a total cost of \(\$ 38.30 .\) The next day, the employees ordered 5 turkey sandwiches and 5 orders of french fries totaling \(\$ 40.75 .\) What does the delicatessen charge for a turkey sandwich? What is the charge for an order of french fries?

Solve by the addition method. $$\begin{aligned} -2 x+7 y &=9 \\ 3 x+2 y &=-1 \end{aligned}$$

Solve by substitution. \(5 x+2 y=0\) \(x-3 y=0\)

Solve by graphing. $$\begin{array}{r} 3 x-2 y=6 \\ y=3 \end{array}$$ (THE GRAPH CANNOT COPY)

An octane number of 87 on gasoline means that it will fight engine "knock" as effectively as a reference fuel that is \(87 \%\) isooctane, a type of gas. Suppose you want to fill an empty 18-gallon tank with some 87-octane gasoline and some 93 -octane fuel to produce a mixture that is 89 -octane. How much of each type of gasoline must you use? (PICTURE NOT COPY)

Solve by substitution. \(2 x-y=2\) \(6 x-3 y=6\)

Solve by the addition method. $$\begin{aligned} &3 x+4 y=4\\\ &5 x+12 y=5 \end{aligned}$$

Food Mixtures A pastry chef created a 50 -ounce sugar solution that was \(34 \%\) sugar from a \(20 \%\) sugar solution and a \(40 \%\) sugar solution. How much of the \(20 \%\) sugar solution and how much of the 40\% sugar solution were used? (PICTURE NOT COPY)

Solve by the addition method. $$\begin{aligned} &2 x+5 y=2\\\ &3 x+3 y=1 \end{aligned}$$