SOLUTION: Can you please help me solve this equation by completing the square. -9x^+18x=16 Thank you!!

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Question 706800: Can you please help me solve this equation by completing the square.
-9x^+18x=16
Thank you!!

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: COMPLETING THE SQUARE solver for quadratics
Read this lesson on completing the square by prince_abubu, if you do not know how to complete the square.
Let's convert -9x%5E2%2B18x%2B-16=0 to standard form by dividing both sides by -9:
We have: 1x%5E2%2B-2x%2B1.77777777777778=0. What we want to do now is to change this equation to a complete square %28x%2Bsomenumber%29%5E2+%2B+othernumber. How can we find out values of somenumber and othernumber that would make it work?
Look at %28x%2Bsomenumber%29%5E2: %28x%2Bsomenumber%29%5E2+=+x%5E2%2B2%2Asomenumber%2Ax+%2B+somenumber%5E2. Since the coefficient in our equation 1x%5E2%2Bhighlight_red%28+-2%29+%2A+x%2B1.77777777777778=0 that goes in front of x is -2, we know that -2=2*somenumber, or somenumber+=+-2%2F2. So, we know that our equation can be rewritten as %28x%2B-2%2F2%29%5E2+%2B+othernumber, and we do not yet know the other number.
We are almost there. Finding the other number is simply a matter of not making too many mistakes. We need to find 'other number' such that %28x%2B-2%2F2%29%5E2+%2B+othernumber is equivalent to our original equation 1x%5E2%2B-2x%2Bhighlight_green%28+1.77777777777778+%29=0.


The highlighted red part must be equal to 1.77777777777778 (highlighted green part).

-2%5E2%2F4+%2B+othernumber+=+1.77777777777778, or othernumber+=+1.77777777777778--2%5E2%2F4+=+0.777777777777778.
So, the equation converts to %28x%2B-2%2F2%29%5E2+%2B+0.777777777777778+=+0, or %28x%2B-2%2F2%29%5E2+=+-0.777777777777778.

Our equation converted to a square %28x%2B-2%2F2%29%5E2, equated to a number (-0.777777777777778).

There is no number whose square can be negative. So, there is no solution to this equation