SOLUTION: If 5x + x squared > 100, then x is not? If 5x - 17 = -x + 7, then x is?

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Question 1067108: If 5x + x squared > 100, then x is not?
If 5x - 17 = -x + 7, then x is?
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
5x+x^2>100
x^2+5x-100>0
x=(1/2)(-5+/- sqrt(25+400)); sqrt (425)=20.62
x=7.81 or -12.81
x is not between -12.81 and 7.81 inclusive.
In the graph below, it is where the function is greater than 0.
graph%28300%2C300%2C-50%2C20%2C-120%2C100%2Cx%5E2%2B5x-100%29
5x-17=-x+7
add xto both sides
6x-17=7
add 17 to both sides
6x=24
x=4
check
20-17=-4+7=3 checks.