Find the methods used to solve every question. Solve the given equations using either, factoring, quadratic formula, completing square, or graphing. Do not use any method more than twice, and use graphing method at least once.
i)3x^2 +11x - 20 = 0
ii)x^2 + 3x - 4 = 0
iii) 3x^2 - x -1 = 0