Question

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

Answer 1

We have real zero of the function, which is `81/17`

Explanation:

In the given function as we will see below terms relating to `x^2` cancel out and hence, the function is a linear one and not quadratic and we do not need quadratic formula. Let us try to solve this.

`y=x^2-x-(x-9)^2`

= `x^2-x-(x^2-18x+81)` - using formula for `(a-b)^2`

= `x^2-x-x^2+18x-81`

= `cancelx^2-x-cancelx^2+18x-81`

= `17x-81`

Hence, we have real zero of the function which is `81/17`