SOLUTION: Solve using the quadratic equation -2x² + 5x = 0

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Question 985684: Solve using the quadratic equation
-2x² + 5x = 0
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
Normally you would not use the quadratic formula to do this 
because it is easier to do by factoring.  However when you
are instructed to use a certain method, you must use it.

-2x² + 5x = 0

Write it with a +0 at the end of the left side:

-2x² + 5x + 0 = 0, so it can be compared to
 ax² + bx + c = 0

and we can see that a=-2, b=5 and c=0.

Then we write the quadratic formula:

x+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29+

and substitute:

x+=+%28-%285%29+%2B-+sqrt%28+%285%29%5E2-4%28-2%29%280%29+%29%29%2F%282%28-2%29%29+

Then simplify:

x+=+%28-5+%2B-+sqrt%2825-0+%29%29%2F%28-4%29+

x+=+%28-5+%2B-+sqrt%2825%29%29%2F%28-4%29+

x+=+%28-5+%2B-+5%29%2F%28-4%29+

We use the + sign

x+=+%28-5+%2B+5%29%2F%28-4%29+

x+=+0%2F%28-4%29+

x+=+0+

So 0 is one solution.

We use the - sign:

x+=+%28-5+-+5%29%2F%28-4%29+

x+=+-10%2F%28-4%29+

x+=+5%2F2+

So 5%2F2 is the other solution.

Edwin