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kitsune0724 Group Title

Simplify: 1/(7x)-1/(5x) and Find a solution: 1/9x+1/10=11/90 please and thank you.

  • one year ago
  • one year ago

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  1. whpalmer4 Group Title
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    \[\frac{1}{7x}-\frac{1}{5x}\]Find a common denominator, then combine. Do you know how to do that?

    • one year ago
  2. kitsune0724 Group Title
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    I think so. Thank you.

    • one year ago
  3. whpalmer4 Group Title
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    For the other one, the same approach is appropriate. Find a common denominator, or multiply the whole equation by the product of all of the denominators.

    • one year ago
  4. kitsune0724 Group Title
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    is it 2/35?

    • one year ago
  5. whpalmer4 Group Title
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    There better be an x in there somewhere, don't you think?

    • one year ago
  6. kitsune0724 Group Title
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    Yes there is. Thank you again.

    • one year ago
  7. some_someone Group Title
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    (1)/(7x)-(1)/(5x) To add fractions, the denominators must be equal. The denominators can be made equal by finding the least common denominator (LCD). In this case, the LCD is 35x. Next, multiply each fraction by a factor of 1 that will create the LCD in each of the fractions. (1)/(7x)*(5)/(5)-(1)/(5x)*(7)/(7) Multiply 1 by 5 to get 5. (5)/(5*7x)-(1)/(5x)*(7)/(7) Multiply 7x by 5 to get 35x. (5)/(35x)-(1)/(5x)*(7)/(7) Multiply -1 by 7 to get -7. (5)/(35x)-(7)/(7*5x) Multiply 5x by 7 to get 35x. (5)/(35x)-(7)/(35x) Combine the numerators of all expressions that have common denominators. (5-7)/(35x) Subtract 7 from 5 to get -2. (-2)/(35x) Move the minus sign from the numerator to the front of the expression. -2/35x

    • one year ago
  8. whpalmer4 Group Title
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    Agree with -2/35x.

    • one year ago
  9. some_someone Group Title
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    (1)/(9)*x+(1)/(10)=(11)/(90) Multiply 1 by x to get x. (x)/(9)+(1)/(10)=(11)/(90) Since (1)/(10) does not contain the variable to solve for, move it to the right-hand side of the equation by subtracting (1)/(10) from both sides. (x)/(9)=-(1)/(10)+(11)/(90) To add fractions, the denominators must be equal. The denominators can be made equal by finding the least common denominator (LCD). In this case, the LCD is 90. Next, multiply each fraction by a factor of 1 that will create the LCD in each of the fractions. (x)/(9)=(11)/(90)-(1)/(10)*(9)/(9) Multiply -1 by 9 to get -9. (x)/(9)=(11)/(90)-(9)/(9*10) Multiply 10 by 9 to get 90. (x)/(9)=(11)/(90)-(9)/(90) Combine the numerators of all fractions that have common denominators. (x)/(9)=(11-9)/(90) Subtract 9 from 11 to get 2. (x)/(9)=(2)/(90) Cancel the common factor of 2 the expression (2)/(90). (x)/(9)=(<X>2<x>)/(45<X>90<x>) Remove the common factors that were cancelled out. (x)/(9)=(1)/(45) Multiply each term in the equation by 9. (x)/(9)*9=(1)/(45)*9 Cancel the common factor of 9 in the denominator of the first term (x)/(9) and the second term 9. (x)/(<X>9<x>)*<X>9<x>=(1)/(45)*9 Reduce the expression by removing the common factor of 9 in the denominator of the first term (x)/(9) and the second term 9. x*1=(1)/(45)*9 Multiply x by 1 to get x. x=(1)/(45)*9 Cancel the common factor of 9 in the denominator of the first term (1)/(45) and the second term 9. x=(1)/(5<X>45<x>)*<X>9<x> Reduce the expression by removing the common factor of 9 in the denominator of the first term (1)/(45) and the second term 9. x=(1)/(5)*1 Multiply 1 by 1 to get 1. x=(1)/(5)

    • one year ago
  10. kitsune0724 Group Title
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    can you please draw it for me? Thank you.

    • one year ago
  11. whpalmer4 Group Title
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    Is the problem \[\frac{1}{9x} + ... \] or \[\frac{1}{9}x + ...\]?

    • one year ago
  12. kitsune0724 Group Title
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    |dw:1359439362873:dw| this is the problem.

    • one year ago
  13. whpalmer4 Group Title
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    \[\frac{1}{9}x + \frac{1}{10} = \frac{11}{90}\] Okay, what should we use as a common denominator?

    • one year ago
  14. whpalmer4 Group Title
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    As 9 and 10 are both factors of 90, I'll take 90 as the common denominator. I'll multiply the first term by 10/10, the second term by 9/9. \[\frac{10}{10}*\frac{1}{9}x + \frac{9}{9}*\frac{1}{10} = \frac{11}{90}\] \[\frac{10x}{90} + \frac{9}{90} = \frac{11}{90}\]Now subtract 9/90 from both sides and solve for x.

    • one year ago
  15. whpalmer4 Group Title
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    Alternatively, I would have multiplied everything by 90 to eliminate the fractions from the outset, but it's good to get some practice working with fractions!

    • one year ago
  16. kitsune0724 Group Title
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    Would it be 9/10?

    • one year ago
  17. whpalmer4 Group Title
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    \[\frac{10x}{90} + \frac{9}{90} - \frac{9}{90} = \frac{11}{90} - \frac{9}{90}\] \[\frac{10x}{90} = \frac{11-9}{90}\]

    • one year ago
  18. kitsune0724 Group Title
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    2/90

    • one year ago
  19. whpalmer4 Group Title
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    \[\frac{10x}{90} = \frac{11-9}{90} = \frac{2}{90}\]Okay, what does x equal?

    • one year ago
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