McGraw Hill Integrated II, 2012
MH
McGraw Hill Integrated II, 2012 View details
2. Complex Numbers
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Exercise 38 Page 182

Recall that sqrt(- a)= isqrt(a).

x = ± 5i

Practice makes perfect
To solve the given equation, let's first isolate x^2.
2x^2+50=0
2x^2=- 50
x^2=- 25
We cannot find any real square roots of a negative number, so we will need to use the fact that sqrt(- a)= isqrt(a) to solve for x.
x^2=- 25
x=± sqrt(- 25)
x=± i sqrt(25)
x=± i * 5
x=± 5i