Asked by vince
solve the inequality,express using interval notation
x3-5x2-14x>0
x3-5x2-14x>0
Answers
Answered by
drwls
First factor it and rewrite as
x (x-7)(x+2) > 0
The function crosses the y axis at x = -2, x=0 and x=7
When x<-2 all three factors are negative, so the function is <0 there
The -2<x<0, two factors are negative and one is positive, so the inequality is satisfied.
Consider also the regions 0<x<7 and x>7 and figure out if the function is positive or negative there.
x (x-7)(x+2) > 0
The function crosses the y axis at x = -2, x=0 and x=7
When x<-2 all three factors are negative, so the function is <0 there
The -2<x<0, two factors are negative and one is positive, so the inequality is satisfied.
Consider also the regions 0<x<7 and x>7 and figure out if the function is positive or negative there.