What are the solutions of the equation x4 + 6x2 + 5 = 0? Use u substitution to solve. x = i and x = iStartRoot 5 EndRoot x = plus-or-minus i and x = plus-or-minus iStartRoot 5 EndRoot x = plus-or-minus StartRoot negative 1 EndRoot and x = plus-or-minus StartRoot negative 5 EndRoot x = plus-or-minus Negative 1 and x = plus-or-minus -StartRoot 5 EndRoot