Question 108141: I can't seem to figure this one out can you help me please?
4n^2 + 20n=0 I have to solve the equation. Found 2 solutions by Fombitz, bucky:Answer by Fombitz(32388) (Show Source):
You can put this solution on YOUR website! You can solve this by first noting that both of the terms on the left side contain the unknown
variable n. Therefore, n can be factored out to give:
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n*(4n + 20) = 0
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Then notice that the left side of this equation will be zero (and therefore equal to the right
side) if either of the two factors on the left side is zero ... because multiplication
by zero results in the product being zero.
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So, this equation will be true if either n = 0 or if 4n + 20 = 0
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You can immediately tell that n = 0 is one solution to the problem. Next you need to solve
the equation 4n + 20 = 0 to find the other value of n that will make the equation true.
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4n + 20 = 0 <==== subtract 20 from both sides to get rid of the + 20 on the left side
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4n = -20 <=== solve for n by dividing both sides by + 4 to reduce the equation:
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n = -20/4 = -5
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In summary, if n = 0 or if n = -5 the equation of the original problem will be true, so
those are the two answers for n.
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You can check these answers by going back to the original problem and substituting them
(one at a time) to make sure the equation is true for that value.
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So start with:
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4n^2 + 20n = 0
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Let n = 0 and the equation becomes:
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4(0)^2 + 20*0 = 0
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This is true because both terms on the left side contain 0 as a multiplier.
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Next let n = -5. When you do the equation becomes:
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4*(-5)^2 + 20(-5) = 0
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Squaring the -5 results in +25, making the equation become:
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4*25 + 20*(-5) = 0
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4*25 is 100 and 20*(-5) is -100 so the equation is equivalent to:
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100 - 100 = 0
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This also is true. So our two answers for n work ... n = 0 and n = -5
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Hope this helps you to understand the problem and how to get the solution.
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