Find the value of a for which (x - 2) is a factor of 3x^2 +

Find the value of a for which (x - 2) is a factor of 3x^2 + ax^2 + x - 2. For this value of a, show that the cubic equation 3x^3 + ax^2 + x - 2 = 0 has only one real root. (OCR 2014)