Just answer this asap for if 9a + 8b + 9c = -9, what is 81c + 72b + 81a?

Which math sentence can be used to determine if the triangle is a right triangle?

The following frequency table relates the weekly sales of bicycles at a given store over a 42-week period.value01234567frequency367108521(a) in how many weeks were at least 2 bikes sold? (b) in how many weeks were at least 5 bikes sold? (c) in how many weeks were an even number of bikes sold?

What is the value of x in the following equation? -3x-2=2x+8