17. [-!1 Points] DETAILS OHOO Submissions Used Let x} 2 x1915". Determine the intervals of concavity of x}. 0 x} is concave up on {2!15,D} and concave down on {00,21'15} U {0,00}. 0 x} is concave up on {00,2f15} and concave down on (2f15,oo). 0 x} is concave up on {ZIISNO) and concave down on (00,2f15}. 0 x} is concave up on {00,2f15} U {0,00} and concave down on (2,!1541}. 0 x} is concave up on {0,00} and concave down on [m,0}