(c) If \( a+b+c=0 \), then prove that: \( \frac{(b+c)^{2}}{3 b c}+\frac{(c+a)^{2}}{3 c a}+\frac{(a+b)^{2}}{3 a b}=1 \) If \( a \)

Solve the following system of equations by the addition method. If the system does not have a single ordered pair as a solution, state whether the system is inconsistent or dependent. \[ \begin{aligned} 4 x+3 y & =-14 \\ 2 x-y & =-12\end{aligned} \]

(a) Find the solution for \( |2 x+1|+3=5 \). Select the correct choice below, and fill in the answer box if necessary. A. The solution set is the finite set of real numbers \( \{ \). (Simplify your answer. Use integers or fractions for any numbers in the expression. Use a comma to separate answers as needed.) B. The solution set is the interval (Type your answer in interval notation. Use integers or fractions for any numbers in the expression.)

Solve the following equations and inequalities analytically. Support your solutions graphically. \( \begin{array}{lll}\begin{array}{ll}\text { (a) }|2 x+1|+3=5 & \text { (b) }|2 x+1|+3 \leq 5 \\ \text { (c) }|2 x+1|+3 \geq 5\end{array} \\ \text { A. The solution set is the finite set of real numbers }\{ \\ \text { (a) Find the solution for }|2 x+1|+3=5 \text {. Select the correct choice below, and fill in the } \\ \text { answer box if necessary. } \\ \text { expression. Use a comma to separate answers as needed.) } \\ \text { B. The solution set is the interval } \square \text {. } \\ \text { (Type your answer in interval notation. Use integers or fractions for any } \\ \text { numbers in the expression.) } \\ \text { C. The solution set is } \varnothing \text {. }\end{array} \).

23. Reasoning Twenty of the students in Hannah's class, or \( 80 \% \) of the class, voted to have pizza fol lunch every Wednesday. How many students are in Hannah's class?

Determine which ordered pair(s) are solutions to the following system. \[ \begin{array}{lll}y=4 x-2 \\ y=-x+23 & (5,18) & (3,-10)\end{array}(2,21) \]