document.write( "Question 160401: I am having trouble finding the varation constant and the equation of the varation where y varies directly as x where y=2 when x=1. \n" ); document.write( "

Algebra.Com's Answer #118326 by Earlsdon(6294) $\"\"$ $\"About$

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The phrase \"y varies directly as x\" is expressed algebraically as:
\n" ); document.write( " $\"highlight%28y+=+kx%29\"$ This is called the equation of variation.
\n" ); document.write( "Notice that we can't write... $\"y+=+x\"$ because we are dealing with the case of how one variable changes when another variable changes, so that we can't really say that they are equal.
\n" ); document.write( "The k, of course, is called the constant of variation, and to find the value of k, we need to know the value of one variable (say, x) and the corresponding value of the other variable, y. These are given in the problem, (y = 2 when x = 1) so we make the substitutions into equation of variation and solve for k.
\n" ); document.write( " $\"1+=+k%282%29\"$ so...
\n" ); document.write( " $\"highlight%28k+=+1%2F2%29\"$ \n" ); document.write( "

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