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 20 Page p10

Begin with the equation x=0.4 and multiply both sides by 10.

4/9

The line over the 4 in the expression 0.4 tells us that the 4 repeats an infinite number of times. 0.4=0.44444... To write the fraction equivalent to this expression, we can use the following equation. x=0.44444... By multiplying both sides of the equation by 10, we create a new equivalent equation. Remember to always follow the Properties of Equality when solving equations.

x=0.44444...
x* 10=0.44444... * 10
10x=4.44444...



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.

10x=4.4444...
10x-x=4.4444...-x
9x=4.4444...-x
9x=4.4444...- 0.44444...
9x=4

Finally, we can divide both sides of the equation by 9 so that the x-variable is isolated. This will leave us with the fraction that is equation to the repeating decimal.

9x=4
9x/9=4/9
x=4/9