Question

How do you solve `x^2 - 4x = 0`?

Answer 1

`(x+2sqrtx)(x-2sqrtx)`

Explanation:

= `x^2-4(sqrtx)^2`

= `x^2-(2sqrtx)^2`

*Use* `a^2-b^2=(a+b)(a-b)`

= `(x+2sqrtx)(x-2sqrtx)`