Question 1111919
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<pre>
Discriminant =  {{{15^2-4*6*(-8)}}} = 417.


Roots   {{{z[1,2]}}} = {{{(-15+- sqrt(417))/12}}} .



{{{(-15-sqrt(417))/12}}} < = z <= {{{(-15+sqrt(417))/12}}}.
</pre>

<U>Be aware</U> :  &nbsp;&nbsp;The answer by &nbsp;@josgarithmetic is &nbsp;&nbsp;<U>W R O N G</U>.