Is y= -9/5x + 1/5 perpendicular to y= 5/9x + 2/9

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9

The angles below are supplementary. what is the value of x? a pair of supplementary angles is shown. one angle measures 7x + 33, and the other angle measures 70. 5.3 8.14 11 14.7

Awater truck is filling a swimming pool. the equation that represents this relationship is y=19.75x where y is the number of gallons of water in the pool and x is the number of minutes the truck has been filling the pool.