Mary can row at the rate of 4 miles per hour in still water. Rowing downstream in a river, she can travel 3 times as far in 1 hour as she can rowing upstream. What is the rate of flow in the river? Please explain :)

The radical equation 2+√2x-3 = √x+7 has a solution set [x= a0} and an extraneous root x = a1.

The parabola x = y² - 9 opens: a.)up b.)down c.) right d.)left

Josh has a rewards card for a movie theater he receives 15 points for becoming a rewards card holder he earns 3.5 points for each visit to the movie theater he needs at least 55 points to earn a free movie ticket which inequality can josh use to determine x, the minimum number of visits he needs to earn his first free movie ticket.