91Ó°ÊÓ

Use a graphing calculator to solve each system. $$ \left\\{\begin{array}{l} {3 x-6 y=4} \\ {2 x+y=1} \end{array}\right. $$

Solve the system by either the substitution or the elimination method. $$ \left\\{\begin{array}{l} {x=5 y-4} \\ {x=9 y-8} \end{array}\right. $$

Solve each system by substitution. If a system has no solution or infinitely many solutions, so state. $$ \left\\{\begin{array}{l} {y-x=3 x} \\ {2 x+2 y=14-y} \end{array}\right. $$

Commemorative Coins. A foundry has been commissioned to make souvenir coins. The coins are to be made from an alloy that is \(40 \%\) silver. The foundry has on hand two alloys, one with \(50 \%\) silver content and one with a \(25 \%\) silver content. How many kilograms of each alloy should be used to make 20 kilograms of the \(40 \%\) silver alloy?

Graph the solutions of each system. $$ \left\\{\begin{array}{l} {y+2 x \leq 0} \\ {y \leq \frac{1}{2} x+2} \end{array}\right. $$

Cleaning Floors. A custodian is going to mix a \(4 \%\) ammonia solution and a \(12 \%\) ammonia solution to get 1 gallon \((128\) fluid ounces) of a \(9 \%\) ammonia solution. How many fluid ounces of the \(4 \%\) solution and the \(12 \%\) solution should be used?

Solve the system by either the substitution or the elimination method. $$ \left\\{\begin{array}{l} {4 x+6 y=5} \\ {8 x-9 y=3} \end{array}\right. $$

Use a graphing calculator to solve each system. $$ \left\\{\begin{array}{l} {6 x-2 y=5} \\ {3 x=y+10} \end{array}\right. $$

In part a, graph the solution of each system. Use your answer to part a to determine the solution of the system of equations in part b. (No new work is needed.) a. \(\left\\{\begin{array}{l}{x+y>-1} \\ {y \geq x-3}\end{array}\right.\) b. \(\left\\{\begin{array}{l}{x+y=-1} \\ {y=x-3}\end{array}\right.\)

Solve each system by substitution. If a system has no solution or infinitely many solutions, so state. $$ \left\\{\begin{array}{l} {y-4=2 x} \\ {y=2 x+2} \end{array}\right. $$