SOLUTION: solve y in the equation y-3y^2-9

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Question 920693: solve y in the equation y-3y^2-9
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

y-3y%5E2-9 set it equal to zero

-3y%5E2%2By-9=0 ...use quadratic formula

y+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ...note that a=-3,b=1, and c=-9

y+=+%28-1+%2B-+sqrt%28+1%5E2-4%2A%28-3%29%2A%28-9%29+%29%29%2F%282%2A%28-3%29%29+

y+=+%28-1+%2B-+sqrt%28+1-108+%29%29%2F%28-6%29+

y+=+%28-1+%2B-+sqrt%28+-107+%29%29%2F%28-6%29+

y+=+%28-1+%2B-+i%2Asqrt%28+107+%29%29%2F%28-6%29+

solutions:

y+=+-1%2F-6+%2B+sqrt%28+107+%29i%2F%28-6%29+

y+=+%281%2F6%29%281+-sqrt%28+107+%29i%29+
or

y+=+-1%2F-6+-+sqrt%28+107+%29i%2F%28-6%29+

y+=+%281%2F6%29%281+%2Bsqrt%28+107+%29i%29+