Question 759367
#2 is a question about the discriminant.


{{{ax^2+bx+c=0}}} has no solution (more correctly stated, no real solution) if {{{b^2-4ac<0}}}.  You are free to choose any value that will work in your problem exercise.  The discriminant in the current equation in your #2 is {{{highlight((-2)^2-4*(-15))=4+60=64}}}