Using the quadratic formula solver Example 2

Solve             `x^2-6x+8=0`

`x=(-b+-sqrt(b^2-4ac))/(2a)`

Quick sketch

Therefore   `a=1` , `b=-6`  &  `c=8`

`x=(-(-6)+-sqrt((-6)^2-4times1times8))/(2times1)`

`x=(6+-sqrt(36-32))/2`

`x=(6+-sqrt4)/2`

`x=(6+-2)/2`

`x=(6+2)/2`   or  `x=(6-2)/2`

`x=8/2`   or  `x=4/2`

`x=4`   or  `2`

 

 

Check the answer

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

 

If `x=4`              `4^2-6times4+8=0`

`16-24+8=0` Which is correct

If `x=2`              `2^2-6times2+8=0`

`4-12+8=0`  Which is correct

Answer:

The roots of `x^2-6x+8=0`  are `x=4`  and `x=2`