(Solved): Need help with 1-3 please, thank you (1 point) Let \( f(x)=-x^{4}-4 x^{3}+7 x+5 \). Find the open in ...

(1 point) Let \( f(x)=-x^{4}-4 x^{3}+7 x+5 \). Find the open intervals on which \( f \) is concave up (down). Then determine the \( x \)-coordinates of all inflection points of \( f \). 1. \( f \) is concave up on the intervals 2. \( f \) is concave down on the intervals 3. The inflection points occur at \( x= \) Notes: In the first two, your answer should either be a single interval, such as \( (0,1) \), a comma separated list of intervals, such as \( (- \) int, 2), \( (3,4) \), or the word "none". In the last one, your answer should be a comma separated list of \( x \) values or the word 'none".