Question 54415: -x^2 > or = 9x+14 Please help!! I have to solve and show the solution in interval and algebraic form. I got through most of the problem but need help with the notation, and also want to confirm that I solved it right. -x^2-9x-14 > or = 0 factored is (-x-2)(x+7) so I got x= -2 and x= -7 as test points and by testing the regions on the number line, I found that -1 through +infinity does not work in the original problem. Im not sure where to go from here or how the interval notation should look. Thanks, Angela
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! (-x-2)(x+7)>=0 so I got x= -2 and x= -7
Draw a number line.
Put -7 and -2 on the line
Test numbers in each of the three intervals:
Interval (-inf,-7]; try -10; (10-2)(-10+7)<0
So, only x=-7 is a solution in this interval.
Interval (-7,-2]; try -5; (5-2)(-5+7)>0;
All x in this interval are part of the solution.
Interval (-2,+inf); try 10: (-10-2)(10+7)<0
So no solutions in this interval.
SOLUTION:
-7<=x<=-2
Cheers,
Stan H.
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