How do you find the roots, real and imaginary, of y= (x-2)^2+(x-4)^2 using the quadratic formula?

1 Answer
Mar 3, 2016

Multiply out and simplify to find a quadratic in standard form, then apply the formula to find zeros x = 3 +-i

Explanation:

y=(x-2)^2+(x-4)^2

=(x^2-4x+4)+(x^2-8x+16)

=2x^2-12x+20

=2(x^2-6x+10)

x^2-6x+10 is in the form ax^2+bx+c with a=1, b=-6 and c = 10.

This has zeros given by the quadratic formula:

x = (-b+-sqrt(b^2-4ac))/(2a)

=(6+-sqrt((-6)^2-(4*1*10)))/(2*1)

=(6+-sqrt(36-40))/2

=(6+-sqrt(-4))/2

=(6+-sqrt(4)i)/2

=(6+-2i)/2

=3+-i