How do you find the roots, real and imaginary, of #y= x^2 + 8x -9- (-x-1)^2 # using the quadratic formula?

1 Answer
Jan 10, 2016

Answer:

x=5/3

Explanation:

There are no imaginary roots of this equation.
To get the roots, put y=0
Now expand #(-x-1)^2# which is actually #(x+1)^2#

#x^2+8x-9-(x^2+2x+1)=0#

#cancel(x^2)+8x-9cancel(-x^2)-2x-1=0#

#6x-10=0#

#x=5/3#

Additionally you can also see that this equation is actually equation of a straight line so it can have at most 1 zero (which is real).