Question

How do you factor completely x square+5x-6

Answer 1

You find two numbers that add up to the  5  and multiply to the  -6 .

It looks like  6  and  -1  can do the job ...

              adding:           6 + (-1)  =  5
              multiplying:     6 x (-1)  =  -6 .

See ? OK.  So now, the factors of the expression are

     ==>  (x plus one of the numbers)
and
     ==>  (x plus the other number).

           (x + 6) (x - 1)  =  x² + 5x - 6 

Answer 2

I'm assuming the "squared" is x^2+5x-6 in which case the answer is (x+6)(x-1)