Question 1200286
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Answer: <font color=red size=4>13/14</font>


Work Shown:


x = the mystery number
x-(-13) = x+13 = decrease the number by -13, i.e. add 13 to the number
15x = the product of 15 and the number


x+13 = 15x
13 = 15x-x
13 = 14x
14x = 13
x = <font color=red>13/14</font>
13/14 = 0.92857 approximately
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