Find the domain of the function. \[ u(x)=\sqrt{-x}+5 \] Write your answer using interval notation.

b). Confirm that \( \phi \) is a porential furetion for \( \hat{F}(z) \) on some region, and state the region. \( \begin{aligned} \phi(x, y, z)= & x \sin z+y \sin x+z \sin y . \\ z(x, y, z)= & (\sin z+y \cos x) i \\ & +(\sin x+z \cos y) j \\ & +(\sin y+x \cos z) k .\end{aligned} \)

What is the equation of the line through point \( (2,1) \) and perpendicular to the line through \( (-4,1) \) and \( (3,-2) ? \) \( \begin{array}{ll}\text { a) } y=\frac{7}{3} x+\frac{11}{3} & \text { go to station } 8 \\ \text { b) } y=\frac{3}{7} x+\frac{11}{3} & \text { go to station } 1 \\ \text { d) } y=-\frac{3}{7} x-\frac{11}{3} & \text { go to station } 10 \\ \text { d) } y=\frac{7}{3} x-\frac{11}{3} & \text { go to station } 5\end{array} \)

Se deja caer en un pozo una piedra que en un principio es- tá en reposo. El sonido del chapoteo se escucha exacta- mente 2.00 s después. Determine la profundidad del pozo si la temperatura del aire es de \( 10.0^{\circ} \mathrm{C} \).

5 bridesmaids want to make 325 decorations for a wedding. Each decoration takes about \( 2 \frac{1}{2} \) minutes to make. Which response gives the best estimate for the amount of time each bridesmaid will spend making decorations?

Solve for \( d \) \[ -8 d+11 d=9 \] \( d= \)