well realistically this problem could be completed without use of quadratic equation:
-2 = -x + 2x - 4
+4 +4
2 = x
However, for quadratic equation, there needs to be 3 numbers:
ax^2+bx+c=0
Putting the equation in this form, we can say that
(0)x^2+(1)x+(-2)=0
Taking that and putting it into the quad formula makes:
x=(-1+-sqrt((1)^2-4(0)(-2)))/2(0)
That makes it a divide by 0 problem, making it unsolveable