What is 40% of 10?
I need to know this for a math question on khan academy

Solve the equation below: (x+4)/6x=1/x a. x=2 b. x=0,2 c. x=-2 d. x=0,-2

What is the measure of ac? 5 units 13 units 26 units 39 units 3x- 2b 6x + 9

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 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)