How do you find the roots, real and imaginary, of y= -13x^2 -5x +11(x-3)^2 using the quadratic formula?

1 Answer
Aug 4, 2016

We have two irrational zeros -71/4-1/4sqrt5833 and -71/4+1/4sqrt5833

Explanation:

y=-13x^2-5x+11(x-3)^2

= -13x^2-5x+11(x^2-6x+9)

= -13x^2-5x+11x^2-66x+99

= -2x^2-71x+99

As discriminant b^2-4ac=(-71)^2-4xx(-2)xx99

= 5041+792=5833 which is positive but not a square of a rational number and hence we have irrational numbers as zeros of te function y=-13x^2-5x+11(x-3)^2 and these are given by quadratic formula

(-(-71)+-sqrt5833)/(-4)=-71/4+-1/4sqrt5833 or

-71/4-1/4sqrt5833 and -71/4+1/4sqrt5833

Note: Only factors of 5833 are 19 and 307.