Find all the values of a for which the equations
x^2 + ax + 1 = 0
x^2 - 3x - a = 0
have a common real root. Enter all the possible values, separated by commas.
in order for the first one to be real, you would need
(x+1)(x+1) where a is 2
or (x-1)(x-1) where a is -2
putting in 2 for a in the second equation is not a real root
putting -2 for a in the second equation gives us
(x-2)(x-1)
this if a=-2 then x=1 is the common root
