Mathematics
RosalynTwito
15

how do solve z^2-6z-27=0 by factoring?

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(1) Answers
lyssie11234

[latex]z^2-6z-27=0\\\\\underbrace{z^2-2z\cdot3+3^2}_{(*)}-3^2-27=0\\\\\\\\(z-3)^2-9-27=0\\\\(z-3)^2-36=0\\\\(z-3)^2=36\iff z-3=-\sqrt{36}\ or\ z-3=\sqrt{36}\\\\z-3=-6\ or\ z-3=6\\\\z=3-6\ or\ z=3+6\\\\z=-3\ or\ z=9[/latex] [latex](*)\ \ \ (a-b)^2=a^2-2ab+b^2[/latex]

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