Solve for x (complex solution)
x=i
x=-i
x=-2i
x=2i
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t^{2}+5t+4=0
Substitute t for x^{2}.
t=\frac{-5±\sqrt{5^{2}-4\times 1\times 4}}{2}
All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. Substitute 1 for a, 5 for b, and 4 for c in the quadratic formula.
t=\frac{-5±3}{2}
Do the calculations.
t=-1 t=-4
Solve the equation t=\frac{-5±3}{2} when ± is plus and when ± is minus.
x=-i x=i x=-2i x=2i
Since x=t^{2}, the solutions are obtained by evaluating x=±\sqrt{t} for each t.
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