quadratic equations: find real, imag. solns for w^2=-225

[fick3]

Find all real or imaginary solutions to the equation. Use the method of your choice.
w^2=-225

I was thinking that I should use the even-root property; but really don't know where to start. Thanks :shock:

 

[pka]

Will \(\displaystyle \pm 15i\) work?

 

[fick3]

could you show me the steps you went through to come up with that answer so I can learn how to do it? Thank you

 

[pka]

By agreement \(\displaystyle i^2=-1\) and we know that \(\displaystyle {15}^2=225\) so \(\displaystyle \left( { \pm 15i} \right)^2 = - 225\).

 

[fick3]

Thank you very much! That helps.

 

[Denis]

in other words:
pretend the negative sign ain't there; so you have 225;
square root of 225 = +- 15;
insert the famous "i" to remind the world there was a negative sign: +- 15 i