How to draw a parabola from an equation.

In which direction does the left side of the graph of this function point? f(x) = 3x3 - x2 + 4x - 2

Arandom sample of n = 25 observations is taken from a n(µ, σ ) population. a 95% confidence interval for µ was calculated to be (42.16, 57.84). the researcher feels that this interval is too wide. you want to reduce the interval to a width at most 12 units. a) for a confidence level of 95%, calculate the smallest sample size needed. b) for a sample size fixed at n = 25, calculate the largest confidence level 100(1 − α)% needed.

Jack has to solve the problem 281-266.how would you tell him to solve the problem ? tell which strategy you would use ,and solve the problem.