4. A bicycle rental company charges a \( \$ 20 \) fee plus \( \$ 5.50 \) per hour to rent a bicycle. Another bicycle rental company charges a \( \$ 15 \) fee plus \( \$ 6.50 \) per hour to rent a bicycle. For what number of hours is the cost for the rental the same?

E Evaluate the function \( f(x)=x^{2}-8 x+3 \) at the given values of the independent variable and simplify

Solve the following system of equations. \[ \begin{array}{l} x+y=-1 \\ 5 y= 10 \\ 4 x+4 y-4 z=-20\end{array} \] Select the correct choice below and, if necessary, fill in the answer boxes to complete your choice. A. There is one solution. The solution is ( (Type integers or simplified fractions.) B. There are infinitely many solutions. The solution set is \( \{(x, y, z) \mid 4 x+4 y-4 z=-20\} \). The solution set is \( \varnothing \).

Para preparar 5 litros de pintura anaranjada se utilizan 3 litros de pintura ama y 2 litros de pintura roja. ¿Qué cantidades se necesitan para preparar 25 litros

3. \( \left\{\begin{array}{l}6 r-5 t=-11 \\ 7 r-8 r=15\end{array}\right. \)

Use the elimination method to find a general solution for the given linear system, where differentiation is with respect to \( t \). \( x^{\prime}=x-y \) \( y^{\prime}=y-9 x \) Eliminate \( x \) and solve the remaining differential equation for \( y \). Choose the correct answer below. A. \( y(t)=C_{1} e^{-2 t}+C_{2} e^{-4 t} \) B. \( y(t)=C_{1} e^{4 t}+C_{2} t e^{4 t} \) D. \( y(t)=C_{1} e^{-2 t}+C_{2} t e^{-2 t} \) E. The system is degenerate. Now find \( x(t) \) so that \( x(t) \) and the solution for \( y(t) \) found in the previous step are a general solution to the system of differential equations. Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. \( x(t)=\square \) B. The system is degenerate.