SOLUTION: can you factor 4xsquared+25

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: can you factor 4xsquared+25      Log On


   

Question 129379: can you factor 4xsquared+25
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Ordinarily, no!
But, if you have studied imaginary numbers,(sqrt%28-1%29, then yes!
4x%5E2%2B25+=+%282x%2B5i%29%282x-5i%29 where: i+=+sqrt%28-1%29
Check using FOIL:
%282x-5i%29%282x%2B5i%29+=+4x%5E2%2B10xi-10xi-%285i%29%285i%29=4x%5E2-%285i%29%5E2+=+4x%5E2-25i%5E2 but i%5E2+=+-1, so...
%282x-5i%29%282x%2B5i%29+=+4x%5E2-25%28-1%29=4x%5E2%2B25