Let `f(x) = x^2+2x+9; x in RR` Determine the set of values of a real constant `lambda` for which the equation `f(x)=lambda` ; that f(x) has no real solution for x.
`f(x) = x^2+2x+9`
`x^2+2x+9 = lambda`
`x^2+2x+9-lambda = 0`
If the above quadratic function does not have real roots then the discriminant(Delta) should be less than 0.
`Delta = 4-4xx1xx(9-lambda)<0`
So for `f(x) = lambda` where there is no solutions `lambda<8`