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anonymous
 5 years ago
What are the solutions of x^2  3x +9 = 0
anonymous
 5 years ago
What are the solutions of x^2  3x +9 = 0

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anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Sarcastic? :( I didn't technically help you.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Well not sarcastic i figured you were at least trying to help so i appreciate that. The problem is still confusing me though? :[

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0You can either work it out with the quadratic formula or completing the square, but the graph does not cross the x axis, so both solutions are imaginary.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0But i did not get two solutions in the problem? :[ im just totally confused on how to solve it :/

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0\[x^2  3x + 9 = 0\] \[\iff \left(x\frac{3}{2}\right)^2  \left(\frac{3}{2}\right)^2 + 9 = 0\] \[\iff \left(x\frac{3}{2}\right)^2 = \frac{27}{4}\] \[\implies x\frac{3}{2} = \pm \sqrt{\frac{27}{4}}\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Of course, you could equally just use the formula, but I think this way is more fun. Do you know how to carry on (mainly with the root) to get the imaginary/complex solution?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Do you see how the working I posted works?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0\[\sqrt{\frac{27}{4}} = \sqrt{1}\cdot\sqrt{\frac{27}{4}} = i\cdot\frac{3\sqrt{3}}{2}\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Again, it may be more 'standard' and easier to repeat if you use the quadratic formula instead, but it would still need you to take the root of a negative number.
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