2x2 -2x - 9 = 0 For this case, what we should do is use the resolver. We have then: x = (- b +/- root (b ^ -4ac)) / 2a a = 2 b = -2 c = -9 Substituting the values: x = (- (- 2) +/- root ((- 2) ^ - 4 (2) (- 9))) / 2 (2) Rewriting: x = (2 +/- root (4 + 72)) / 4 x = (2 +/- root (76)) / 4 x = (2 +/- root (19 * 4)) / 4 x = (2 +/- 2raiz (19)) / 4 x = (1 +/- root (19)) / 2 Answer: option C x = (1 +/- root (19)) / 2
