SOLUTION: solve the equation x^2=-81

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: solve the equation x^2=-81      Log On


   

Question 68424: solve the equation x^2=-81
Answer by rmromero(383) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E2+=+-81
1. To solve for x, extract the square root both sides
sqrt+%28x%5E2%29+=+sqrt+%28-81%29


+x+=+sqrt+%28-81%29
+x+=+sqrt+%28%28-1%29%2881%29%29

Note: sqrt+%28-1%29+=+i+ and sqrt%2881%29+=+9
highlight+%28x+=+9i%29