Suppose that the augmented matrix of a system of linear equations for unknowns \( x, y \), and \( z \) is \( \left[\begin{array}{ccc:c}1 & -\frac{7}{2} & \frac{11}{4} & -6 \\ 5 & -\frac{35}{2} & \frac{55}{4} & -30 \\ -4 & 14 & -11 & 24\end{array}\right] \). Solve the system and provide the information requested.

Simplify. \[ \frac{10 y^{2}-25 y}{5 y^{2}-15 y} \]

10. Matador Wireless offers a data plan that charges \( \$ 10.00 \) a month for access, with no additional charge if usage is at or below 75 MB . If a customer exceeds 75 MB of data they are also charged 10 cents for each MB above 75 . If a customer exceeds 125 MB of data, they are charged 40 cents for each MB above 125 . a. What is the monthly cost to store 125 MB of data? b. Write a formula for the piecewise function of the cost function for storing \( x \mathrm{MB} \) of data a month. Fill in the boxes for the piecewise definition for the cost \( C(x) \) of storing \( x \) MB of data a month. \[ C(x)=\left\{\begin{array}{cc}10 & \text { if } 0 \leq x \leq 75 \\ 10+0.10(x-75) & \text { if } 75<x \leq 125 \\ 10+0.10(50)+0.40(x-125) & \text { if } x>125\end{array}\right. \]

Solve the equation. If necessary, round to the nearest thousandth. \( 7^{x+3}=6^{x} \) A. \( \{37.87\} \) B. \( \{-39.33\} \) C. \( \{-37.87\} \) D. \( \{-36.41\} \)

a) \( 7 x+(3 x-5)=6 x-9 \)

\( | \frac { 2 x - 1 } { x + 1 } - 2 | < \varepsilon \)