Help me with these answers and please number which question you’re doing so I don’t get confused

Which expression is equivalent to the expression below? (6c^2 + 3c) / (-4c + 2) / (2c + 1) / (4c - 1)a. 3c(2c-1) / (2c + 1)b. -3c(2c-1)^2 / (2c + 1)^2c. 3cd. -3c(just took the test its d. -3c)

Ammonia molecules have three hydrogen atoms and one nitrogen atom.how many of each atom arein five molecules of ammonia

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 0 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)