Math CentralQuandaries & Queries


Question from Melissa, a student:

can u please help me with this question?
13 = x/20

Hi Melissa,

An equation is a balance with the balance point at the equal sign and equal amounts on each side. The challenge is to manipulate the equation, always maintaining a balance, and end with an equation x = "some number".

You have 13 = x/20 and you need to manipulate the equation so that the symbol x is alone on one side. To maintain the balance, whatever you do on one side of the equation you must also do on the other. In this case multiply each side of the equation by 20. This gives

13 = x/20 so
13 × 20 =  x/20 × 20 and hence
260 = x or equivalently
x = 260

I hope this helps,

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