I need help with these homework questions.

23# Determine the location of each local extremum of the function.

f(x)= 4/3 x^3 - 21/2 x^2 + 5x +3

35# use the first derivative test to determine the location of each local extremum and the value of the function at this extremum.

f(x)= x^2 -2x+1/ x-3

#27 Find the largest open intervals on which each function is concave upward or concave downward and find the location of any points of inflection.

f(x) = x^3 + 4x^2 -6x +3

#43 Find all critical numbers of the functions. Then use the second derivative test on each critical number to determine whether it leads to a local maximum or minimum.

f(x)= x+ 4/x