Marsha rode for a while at 20 miles per hour with Bertha and completed the 280 -mile trip by riding with Sherri at 45 miles per hour. If the total trip took 9 hours, how far did she ride with each friend?

The dealer paid $\$ 4000$ for the car and sold it for $\$ 5000$. What was the percent markup of the purchase price, and what was the percent markup of the selling price?

The druggist began with $240 \mathrm{ml}$ of a $20 \%$ antiseptic solution. How much pure antiseptic should be added to get a solution that is $52 \%$ antiseptic?

Solve $3 x^2-x-7=0$ by completing the square.

Complete the square as an aid in graphing:

$$y=-x^2+2 x-3$$

Complete the square as an aid in graphing:

$$y=x^2-4 x+7$$

Solve:

$$\left\{\begin{array}{l}\frac{1}{2} x+\frac{1}{4} y=7 \\ 0.7 x-0.02 y=5.36\end{array}\right.$$

Expand:

$$\left(x^{1 / 4}-y^{-1 / 4}\right)^2$$

Complete the square as an aid in graphing:

$$y=-x^2-4 x-6$$

Find the concentration of hydrogen ions $\left(\mathrm{H}^{+}\right)$in moles per liter when the $\mathrm{pH}$ of the liquid is $2.23$.

Graph the solutions:

$$\{x \in J|| x \mid-3>-7\}$$

Solve:

$$\left\{\begin{array}{l}x^2+y^2=4 \\ x-y=1\end{array}\right.$$

Find the equation of the line through $(5,-7)$ that is perpendicular to $x+3 y-4=0$.

Solve:

$$\left\{\begin{array}{l}x+2 y=10 \\ x-3 z=-16 \\ y+2 z=16\end{array}\right.$$