How do you solve # 9a=-a²-18#?

1 Answer
Burglar
May 29, 2016

#a=-3#, and #a=-6#.

Explanation:

Start bringing everything on the same side changing the sing when you "jump" the #=# symbol.

#a^2+9a+18=0#

Now you can use the formula for the second order equation

#a=(-9\pmsqrt(81-4*18))/2=(-9\pmsqrt(9))/2=(-9\pm3)/2#.
The solution with the #+# is
#a=-3#
and the solution with the #-# is
#a=-6#.

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