Simplify. 6. \( \frac{a^{2} b^{2} c}{12 a^{2} c^{2}} \)

Use Gaussian elimination to find the complete solution to the following system of equations, or show that none exists. \( \left\{\begin{aligned}-x+y+z=-1 \\ -x+5 y-15 z=-13 \\ 3 x-2 y-7 z=\end{aligned}\right. \) Select the correct choice below and, if necessary, fill in the answer boxes to complete your choice. A. There is one solution. The solution set is \( \{(\square, \square)\} \) (Simplify your answers.) B. There are infinitely many solutions. The solution set is \( \{(\square, \square, z)\} \), where \( z \) is any real number. (Type expressions using \( z \) as the variable. Use integers or fractions for any numbers in the expressions.) C. There is no solution. The solution set is \( \varnothing \).

3-. Dados los conjuntos: \( A=\left(x \in R / \frac{x-1}{2}-\frac{x-2}{3} \geq 1\right) . \quad B=(x \in R /-3-2 x \geq 2\} \) y \( \quad C=\{x \in / 1 \leq 2-3 x<\mid 6\} \) a) Escribe a cada uno de ellos como intervalo.

6. Find the solution. \( \quad 6 y-1=2(y+8) \)

Which two equations below have a solution of \( x=-5 \) ?

\( \begin{aligned} \text { d. } y & =2 x+3 \\ y & =5 x+12\end{aligned} \)