Question 50817: solve the quadratic inequality , and graph the solution on the number line. (x+1)(x-9)less than 0
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! solve the quadratic inequality , and graph the solution on the number line. (x+1)(x-9)less than 0.
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Draw the number line and mark x=-1 and x=9 as they are the zero
points for your inequality.
Now, examine the inequality with values from each of the three segments
created on the number line by these points.
In interval I, which is (-infinity,-1), choose x=-10.
You get (-10+1)(-10-9) which is >0, so there are no
solutions in interval I.
In interval II, which is (-1,9) choose x=0.
You get (0+1)(0-9) which is <0, so interval II is
part of the solution of the inequality.
In interval III, which (9,+infinity), choose x=10.
You get (10+1)(10-9), which is >0 so there are no
solutions in interval III.
SOLUTION:
-1
cheers,
Stan H.
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