How do you find the zeros, real and imaginary, of #y=-x^2- x +5# using the quadratic formula?

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Answer 1 · 2016-06-10T13:09:44

Zeros of #y=-x^2-x+5# are

#(-1-sqrt21)/2# and #(-1+sqrt21)/2#

Quadratic formula gives the roots or zeros of general form of quadratic equation #ax^2+bx+c# as #(-b+-sqrt(b^2-4ac))/(2a)#

Hence zeros of #y=-x^2-x+5# are

#(-(-1)+-sqrt((-1)^2-4xx(-1)xx5))/(2*(-1))# or

#(1+-sqrt(1+20))/(-2)# or

#(-1+-sqrt21)/2# or

i.e. #(-1-sqrt21)/2# and #(-1+sqrt21)/2#