Find the derivative of f(x) = 12x^2 + 8x at x =9

The number of fish in a lake can be modeled by the exponential regression equation y=14.08 x 2.08^x where x represents the year

If f(x)= sqrt4x+9+2, which inequality can be used to find the domain of f(x)?

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.