SOLUTION: solving a quadratic equation? x^2=-16

Algebra ->  Rational-functions -> SOLUTION: solving a quadratic equation? x^2=-16      Log On


   

Question 187433: solving a quadratic equation?

x^2=-16
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E2=-16 Start with the given equation.


x=0+%2B-+sqrt%28-16%29 Take the square root of both sides.


x=sqrt%28-16%29 or x=-sqrt%28-16%29 Break up the "plus/minus"


x=sqrt%28-1%2A4%5E2%29 or x=-sqrt%28-1%2A4%5E2%29 Factor -16 into -1%2A4%5E2


x=sqrt%28-1%29%2Asqrt%284%5E2%29 or x=-sqrt%28-1%29%2Asqrt%284%5E2%29 Break up the square root.


x=i%2Asqrt%284%5E2%29 or x=-i%2Asqrt%284%5E2%29 Replace sqrt%28-1%29 with i


x=i%2A4 or x=-i%2A4 Take the square root of 4%5E2 to get 4


x=4i or x=-4i Rearrange the terms.



So the solutions are x=4i or x=-4i (which are complex).