SOLUTION: I AM SUPOSED TO USE i for this but the teacher did not explain how x^2=-16 8x^2=-2 x^2=-30 please help thank you for your time

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: I AM SUPOSED TO USE i for this but the teacher did not explain how x^2=-16 8x^2=-2 x^2=-30 please help thank you for your time      Log On


   

Question 24680: I AM SUPOSED TO USE i for this but the teacher did not explain how
x^2=-16
8x^2=-2
x^2=-30
please help
thank you for your time
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
i+=+sqrt%28-1%29
x%5E2+=+-16
take the square root of both sides
x+=+sqrt%28-16%29
note that sqrt%28-16%29+=+sqrt%28-1+%2A+16%29
and that equals sqrt%28-1%29+%2A+sqrt%2816%29
so
x+=+i+%2A+sqrt%2816%29
x+=+%2B-+%28i+%2A+4%29
next problem:
8%2A+x%5E2+=+-2
x%5E2+=+-%281%2F4%29
x+=+sqrt%28+-1%29+%2A+sqrt%281%2F4%29
x+=+%2B-+%28i+%2A+%281%2F2%29%29
next problem:
x%5E2+=+-30
x+=+sqrt%28-30%29
x+=+sqrt%28-1%29+%2A+sqrt%2830%29
x+=+%2B-+%28i+%2A+5.5%29