91Ó°ÊÓ

Solve each system of equations by the substitution method. $$ \left\\{\begin{array}{l} 10 x-5 y=-21 \\ x+3 y=0 \end{array}\right. $$

Solve each system of equations by the substitution method. $$ \left\\{\begin{array}{l} 3 x-y=1 \\ 2 x-3 y=10 \end{array}\right. $$

Solve each system of equations by the addition method. If a system contains fractions or decimals, you may want to first clear each equation of fractions or decimals.$$ \left\\{\begin{array}{l} 2 x-5 y=4 \\ 3 x-2 y=4 \end{array}\right. $$

Pratap Puri rowed 18 miles down the Delaware River in 2 hours, but the return trip took him \(4 \frac{1}{2}\) hours. Find the rate Pratap can row in still water, and find the rate of the current. Let \(x=\) rate Pratap can row in still water and \(y=\) rate of the current

Solve each system of equations by the addition method. If a system contains fractions or decimals, you may want to first clear each equation of fractions or decimals.$$ \left\\{\begin{array}{l} 6 x-5 y=7 \\ 4 x-6 y=7 \end{array}\right. $$

Solve each system of equations by the substitution method. $$ \left\\{\begin{array}{l} 2 x-y=-7 \\ 4 x-3 y=-11 \end{array}\right. $$

The Jonathan Schultz family took a canoe 10 miles down the Allegheny River in \(1 \frac{1}{4}\) hours. After lunch it took them 4 hours to return. Find the rate of the current. Let \(x=\) rate the family can row in still water and \(y=\) rate of the current

Dave and Sandy Hartranft are frequent flyers with Delta Airlines. They often fly from Philadelphia to Chicago, a distance of 780 miles. On one particular trip they fly into the wind, and the flight takes 2 hours. The return trip, with the wind behind them, takes only \(1 \frac{1}{2}\) hours. Find the speed of the wind and find the speed of the plane in still air.

Solve each system of equations by the substitution method. $$ \left\\{\begin{array}{l} -x+2 y=10 \\ -2 x+3 y=18 \end{array}\right. $$

Solve each system of equations by the addition method. If a system contains fractions or decimals, you may want to first clear each equation of fractions or decimals.$$ \left\\{\begin{array}{l} \frac{x}{3}+\frac{y}{6}=1 \\ \frac{x}{2}-\frac{y}{4}=0 \end{array}\right. $$