SOLUTION: Could someone please help me with solving the following equation: 10x^2+9x=-2 Thanks

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Question 73271: Could someone please help me with solving the following equation:
10x^2+9x=-2
Thanks

Answer by bucky(2189) About Me  (Show Source):
You can put this solution on YOUR website!
Solve:
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10x%5E2%2B9x=-2
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The first thing to do is to add +2 to both sides of this equation to eliminate the -2 on the
right side and get the standard quadratic form of:
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10x%5E2+%2B+9x+%2B+2+=+0
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There are several ways you can solve this equation.
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For example your can graph y+=+10x%5E2+%2B9x%2B2 and the values of x that you are looking for
will be at the points where the graph crosses the x-axis.
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Or you can factor the equation, if it is easily factored. (This one can be factored.)
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Or you can use the quadratic formula.
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Usually the order in which you learn to do these is just as listed above. I'm going to
assume that you understand how to factor. The factors for the 10x%5E2 term are either
(10x and x) or (5x and 2x). And the factors of the constant 2 are (2 and 1). Now all
you have to do is to figure out what combination of numbers and signs will result in a
middle term of 9x.
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You can do the detailed work and thought, but I'll tell you that the answer is:
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%282x+%2B+1%29%2A%285x+%2B+2%29
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Put these back into the equation to get:
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%282x+%2B+1%29%2A%285x+%2B+2%29=0
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This equation will be true if either one of the factors equals zero because a factor of
zero on the left side will make the whole left side zero, and that will equal the right side.
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So, set:
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2x+%2B1+=+0
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and solve by first subtracting 1 from both sides to get:
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2x+=+-1
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Finally divide both sides by 2 and you find that:
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x+=+-1%2F2
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But the other factor can be zero also. So this time let the other factor equal zero and solve:
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5x+%2B+2+=+0
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Subtract 2 from both sides to find that:
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5x+=+-2
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Then divide both sides by 5 to get:
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x+=+-2%2F5
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So the two answers to this problem are x+=+-1%2F2 and x+=+-2%2F5.
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Hope that this answers your question in a method you understand. Graphing to solve this
would be a little time consuming because the answers are not "nice" (because they are not
integers). The quadratic formula is a good method to solve any quadratic equation, but
it can be a little challenging if you have not at least studied it a little.