Please show all work including algebra. Thank you.

4 Find the critical numbers of the function a J = 3 2 + 18 x b 9 ( x ) = xx - 82 + 13 C f ( x ) = vx ( x - 3 ) 15 Find the open intervals on which the function is increasing or decreasing a y = - 5x + 8 x b for ) = 6 @ If fix ) has a relative minimum or relative maximum at X = C, then cis a critical number f f loe ) . That is either Find all relative extrema of f ( x ) = 2 x + 15 x - 8 use the first derivative rest to find all relative extrema of the function f( x ) = 2 - 3x