Question

How do you solve `x^2 – 7x – 1 = -7` using the quadratic formula?

Answer 1

Solution is `6` and `1`

Explanation:

For an equation `ax^2+bx+c=0`, quadratic formula gives the solution as `(-b+-sqrt(b^2-4ac))/(2a)`.

As in the given equation `x^2-7x-1=-7` or `x^2-7x+6=0` i.e. `a=1, b=-7` and `c=6`

Solution is given by `(-(-7)+-sqrt((-7)^2-4*1.6))/(2*1)` or

`(7+-sqrt(49-24))/2` or `(7+-sqrt25)/2` or `(7+-5)/2`

Hence solution is `6` and `1`