SOLUTION: Determine the nature of the solutions of the equation x^2-18=0. Does it have 1 solution, 2 imaginary solutions, or 2 real solutions? Thank you!

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Determine the nature of the solutions of the equation x^2-18=0. Does it have 1 solution, 2 imaginary solutions, or 2 real solutions? Thank you!      Log On


   

Question 221485: Determine the nature of the solutions of the equation x^2-18=0. Does it have 1 solution, 2 imaginary solutions, or 2 real solutions?
Thank you!
Found 2 solutions by user_dude2008, jim_thompson5910:
Answer by user_dude2008(1862) About Me  (Show Source):
You can put this solution on YOUR website!
2 real solutions

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

From x%5E2-18 we can see that a=1, b=0, and c=-18


D=b%5E2-4ac Start with the discriminant formula.


D=%280%29%5E2-4%281%29%28-18%29 Plug in a=1, b=0, and c=-18


D=0-4%281%29%28-18%29 Square 0 to get 0


D=0--72 Multiply 4%281%29%28-18%29 to get %284%29%28-18%29=-72


D=0%2B72 Rewrite D=0--72 as D=0%2B72


D=72 Add 0 to 72 to get 72


Since the discriminant is greater than zero, this means that there are two real solutions.