2010 AIME II Problems/Problem 7

Revision as of 11:56, 3 April 2010 by Sinkokuyou (talk | contribs)

set $w=x+yi$, so $x_1 = x+(y+3)i$, $x_2 = x+(y+9)i$, $x_3 = 2x-4+2yi$. Since $a,b,c\in{R}$, the imaginary part of a,b,c must be 0. Start with a, since it's the easiest one to do: $y+3+y+9+2y=0, y=-3$ and therefore: $x_1 = x$, $x_2 = x+6i$, $x_3 = 2x-4-6i$ now, do the part where the imaginery part of c is 0, since it's the second easiest one to do: x(x+6i)(2x-4-6i), the imaginery part is: 6x^2-24x, which is 0, and therefore x=4, since x=0 don't work, so now, $x_1 = 4, x_2 = 4+6i, x_3 = 4-6i$

Invalid username
Login to AoPS