91Ó°ÊÓ

Solve each inequality. Write the solution set in interval notation and graph it. $$ -4(2 y+2) \leq 4 y+28 $$

What concept does this diagram illustrate? $$ \left\\{\begin{array}{l} {6 x+5 y=11} \\ {y=(3 x-2)} \end{array}\right. $$

Solve each inequality. Write the solution set in interval notation and graph it. $$ -5<3 t+4 \leq 13 $$

Explain the error. Solve: \(\quad\left\\{\begin{array}{l}{3 a+4 b=1} \\ {a+2 b=9}\end{array}\right.\) \(a=9-2 b \quad\) Solve for \(a\) in the second equation. \(9-2 b+2 b=9 \quad\) Substitute \(9-2 b\) for \(a\) \(\begin{aligned} 9=9 & \text { The b-terms drop out. } \\ \text { True } \end{aligned}\) The system has infinitely many solutions.

Solve the system by either the substitution or the elimination method. $$ \left\\{\begin{array}{l} {11 c+3 d=-68} \\ {10 c+3 d=-64} \end{array}\right. $$

When using the substitution method, how can you tell whether a. a system of linear equations has no solution? b. a system of linear equations has infinitely many solutions?

Solve the system by either the substitution or the elimination method. $$ \left\\{\begin{array}{l} {\frac{2}{15} x-\frac{1}{5} y=\frac{1}{3}} \\ {\frac{2}{15} x-\frac{1}{5} y=\frac{1}{10}} \end{array}\right. $$

Solve each inequality. Write the solution set in interval notation and graph it. $$ -1 \leq-\frac{1}{2} n $$

Solve each inequality. Write the solution set in interval notation and graph it. $$ \frac{1}{3}+\frac{c}{5}>-\frac{3}{2} $$

Solve the system by either the substitution or the elimination method. $$ \left\\{\begin{array}{l} {\frac{1}{5} x+\frac{3}{5} y=\frac{4}{5}} \\ {\frac{1}{6} x+\frac{1}{2} y=\frac{2}{3}} \end{array}\right. $$