Question

How do you solve `5x^{2} - 25x = 5x - 40`?

Answer 1

`x=4, x=2`

Explanation:

`5x^2-25x=5x-40`

Thus `x^2-5x=x-8`

`x^2-6x+8=0`

We could use the quadratic formula; alternatively we could factorize the expression:

`(x-4)(x-2)=0`

Which clearly has roots at `x=4, "and "x=2`.