Answers

2014-08-31T23:28:30+08:00
 3x ^2 + 13x - 10 \leq  0  \\ \\first\  we \ solve: \\ 3x ^2 + 13x - 10\\ (x + 5) (3 x - 2)=0 \\x+5=0 \ \ or \ \ 3x-2=0 \\x=-5\ \ or \ \ 3x= 2 \\ x=-5\ \ or \ \  x= \frac{2}{3}

 a  >  0 open for up .  

So we know that the curve is u-shaped and that it crosses
the x-axis at x=- \frac{2}{3} and x=-5.


The curve is less than zero   :    x \geq -5 \ and \ x \leq \frac{2}{3}




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