Question 198582: How would i graph x^2+2x-15>0 on a number line? I factored the equation to (x+5)(x-3)>0. than i solved for x and got x>-5 and x>3. so when i graphed it on a number line one starts at -5 and goes to the right and the other starts at 3 and goes to the right. The answer is suppose to be graphted with starting at the -5 and going to the left and starting with the 3 and going to the right. what am i missing. this question is not from a textbook. thanks
Answer by RAY100(1637)   (Show Source):
You can put this solution on YOUR website! x^2 +2x -15 >0
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this is a quadratic, degree 2, and therefore is traditionally graphed on a x -y coordinate system
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Let y > x^2 +2x -15, and graph
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T Box might be
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X,,,,,,,,,Y
0,,,,,,,,,-15
-5, 3 ,,0
-1,,,,,,-16
-2,,,,,,-15
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plotting these we see and upward facing y parabola, with vertex at (-1,-16)
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The area of concern is below the curve, which is shown as a dashed line.
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Test point confirms, at x=0, y = -15 which is <0
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