SOLUTION: the sum of the squares of two consecutive positive even integers is 340. find the integers.

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Question 110012This question is from textbook algebra(structure and method)
: the sum of the squares of two consecutive positive even integers is 340. find the integers. This question is from textbook algebra(structure and method)

Answer by bucky(2189) About Me  (Show Source):
You can put this solution on YOUR website!
Begin by letting x equal one of the positive even integers. Then the next consecutive
positive even integer is x + 2 (because even numbers are 2 units away from the preceding
even integer.)
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Square the two integers to get x%5E2 and %28x%2B2%29%5E2+=+x%5E2+%2B+4x+%2B+4. Then add these
two squares and get:
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x%5E2+%2B+x%5E2+%2B+4x+%2B+4
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You can combine the two x%5E2 terms to simplify this to:
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2x%5E2+%2B+4x+%2B+4
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and you are told that this sum equals 340. In equation form this is:
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2x%5E2+%2B+4x+%2B+4+=+340
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You can simplify this a little by dividing both sides (each term) by 2 because 2 is a factor
of all the terms in this equation. Dividing by 2 results in:
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x%5E2+%2B+2x+%2B+2+=+170
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Get this into standard quadratic form by subtracting 170 from both sides of the equation so
that the right side is zero. This subtraction leads to:
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x%5E2+%2B+2x+-+168+=+0
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The left side of this equation can be factored. This factoring leads to:
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%28x+%2B+14%29%2A%28x+-+12%29+=+0
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This equation will be true if either of the factors is zero, because a multiplication
by zero on the left side results in the entire left side becoming zero and therefore
equal to the right side. So find out what values of x cause a factor to equal zero by
setting each factor equal to zero:
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+x+%2B+14+=+0
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Solve by subtracting 14 from both sides to get:
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x+=+-14
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So one of the integers that could satisfy this equation is -14, but we can eliminate
this because the problem requires that the consecutive even integers be positive.
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Setting the other factor equal to zero:
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x+-+12+=+0
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Solve for x by adding 12 to both sides to get:
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x+=+12
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This answer tells us that the first positive even integer is 12, and therefore, then next
consecutive even integer is 14.
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Check these answers. Does 12%5E2+%2B+14%5E2+=+340? Yes it does because 12%5E2+=+144 and 14%5E2+=+196.
So our check is 144+%2B+196+=+340 and this means that our answer works.
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The answer to this problem is that two consecutive positive even integers that work are 12 and 14
because when their squares are summed, the total is 340.
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Hope this helps you to understand the problem.
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