Please help this is math

Which expression is equal to (21)(7)(3x) using the associative property? (21 · 7 · 3)x (7)(21)(3x) 32(7 + 3x) (3x)(7)(21)

Need match the functions with correct transformation. f(x) = -3x f(x) = |x-1|+3 f(x) = √(x+3) 1/2x² f(x) = (x+1)²-3 4|x| 1. compress by a factor of 1/2 2. stretch by a factor of 4 3. shift to the left 3 4. shift to the left 1 5. shift up 3 6. reflection

The serenity and the mystic are sail boats. the serenity and the mystic start at the same point and travel away from each other in opposite directions. the serenity travels at 16 mph and the mystic travels at 19 mph. how far apart will they be in 3 hours?