McGraw Hill Glencoe Algebra 1, 2012
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McGraw Hill Glencoe Algebra 1, 2012 View details
2. Real Numbers
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Exercise 21 Page p10

Begin with the equation x=0.13 and multiply both sides by 100.

13/99

The line over the 13 in the expression 0.13 tells us that the 13 repeats an infinite number of times. 0.13=0.131313... To write the fraction equivalent to this expression, we can use the following equation. x=0.131313... By multiplying both sides of the equation by 100, we create a new equivalent equation. Remember to always follow the Properties of Equality when solving equations.

x=0.131313...
x* 100=0.131313... * 100
100x=13.131313...

Now, we can subtract x from both sides to eliminate the repeating decimal. This is possible because we know that x is equal to the decimal part.

100x=13.131313...
100x-x=13.131313...-x
99x=13.131313...-x
99x=13.131313...- 0.131313...
99x=13

Finally, we can divide both sides of the equation by 99 so that the x-variable is isolated. This will leave us with the fraction that is equation to the repeating decimal.

99x=13
99x/99=13/99
x=13/99