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

1 Answer
Nov 5, 2017

y has two complex roots: x=1/4(-1+- sqrt31 i)

Explanation:

y=x^2-3x+(-x-2)^2

The roots of y occur where y=0

:. x^2-3x+(-x-2)^2 =0

Expanding:

x^2-3x+x^2+4x+4=0

Combining like terms:

2x^2+x+4=0

Apply the quadratic formula:

x= (-1+-sqrt((1)^2 - 4xx2xx4))/(2xx2)

= (-1+-sqrt(1-32))/4

= (-1+-sqrt(-31))/4

= (-1+-sqrt(31xx(-1)))/4

=1/4(-1+- sqrt31 i)

y has two complex roots: x=1/4(-1+- sqrt31 i)