How to determine the square root from -21+20i?

[cyan elbow]

adonhs

[raven cargo]

So you can rewrite the above as in the step below.

[ocean osprey]

Sorry, but, what would I be substituting with?

[raven cargo]

x² = u for example

to make it quadratic

then use the quadratic formula, calculate the solutions in terms of u and resubstitute to calculate the solutions in terms of x.

[ocean osprey]

Ohh, alright, thank you for helping me out!

[gentle ledge]

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[raven cargo]

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