- #1

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Solve the equation:

n/n+3 + 7/n+4 = 1

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- Thread starter Gringo123
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- #1

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Solve the equation:

n/n+3 + 7/n+4 = 1

- #2

Cyosis

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You want to get rid of the denominators first, then collect terms.

- #3

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- #4

Cyosis

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You can bring them under the same denominator by cross multiplying. Hint: what method would you use to add 1/3+1/4 together?

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- #5

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- #6

Cyosis

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Exactly, now apply the same procedure to the two fractions in your equation.

- #7

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Am I on the right track?

- #8

Cyosis

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- #9

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n+3 + n+4 = 2n + 7. Is that the common denominator I should be using?

maybe 7 + n / 2n + 7?

- #10

Cyosis

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Perhaps an intermediate step. lets define a=n+3 and b=n+4. Can you add 1/a+1/b together in terms of a and b?

- #11

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Since "n + 3" and "n + 4" are relatively prime, we must multiply them together to get their LCM. This is analogous to LCM(3,4) = 12 (NOT SEVEN!!!)

If you multiply the entire equation by the LCM/LCD, there will be no more fractions.

(But there will be a quadratic equation to solve...)

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