How do you solve the equation 3/(3x) + 1/(x + 4) = 10/(7x)?

To solve the equation 3/(3x) + 1/(x + 4) = 10/(7x), we need to find the value of x. Let’s break down the steps:

  1. Find a common denominator: The left side has two fractions, one with a denominator of 3x and the other with x + 4. The least common denominator (LCD) of the left-hand side would be 3x(x + 4). For the right side, the denominator is 7x. Therefore, the overall common denominator will be 21x(x + 4).
  2. Rewrite each term using the common denominator:
    • For the first fraction, multiply both the numerator and the denominator by (x + 4):
      (3/(3x)) * ((x + 4)/(x + 4)) = 3(x + 4)/(3x(x + 4))
    • For the second fraction, multiply both the numerator and the denominator by 3x:
      (1/(x + 4)) * (3x/3x) = 3x/(3x(x + 4))
    • For the right side, multiply both the numerator and the denominator by 3(x + 4):
      (10/(7x)) * (3(x + 4)/(3(x + 4))) = 30(x + 4)/(21x(x + 4))
  3. Combine the fractions on the left side:
    The left side can now be written as:
    (3(x + 4) + 3x) / (21x(x + 4)) = 30(x + 4)/(21x(x + 4))
  4. Eliminate the denominators: Since both sides of the equation are fractions with the same denominators, we can set the numerators equal to each other:
    3(x + 4) + 3x = 30(x + 4)
  5. Simplify the equation:
    1. Expand the left side:
    3x + 12 + 3x = 30x + 120
    6x + 12 = 30x + 120
  6. 2. Rearrange to isolate x:
    6x – 30x = 120 – 12
    -24x = 108
  7. 3. Solve for x:
    x = -108/24
    x = -4.5

Thus, the solution to the equation 3/(3x) + 1/(x + 4) = 10/(7x) is x = -4.5.

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