The quadratic equation $2x^2 + bx + 18 = 0$ has a double root. Find all possible values of $b.$
2x^2 + bx + 18 = 0
If this has a double root......the discriminant will = 0
b^2 - 4(2)(18) = 0
b^2 - 144 = 0
b^2 = 144 take both roots
b = 12 or b = -12