document.write( "Question 618635: Direct and Indirect Variation. I do not understand how to solve this or any problems such as these. \r
\n" ); document.write( "\n" ); document.write( "y varies directly with x. y =15 when x=4. what is the value of y when x=5\r
\n" ); document.write( "\n" ); document.write( "or y varies inversely with x y=8 when x=8. what is the value of y when x=4 \n" ); document.write( "
Algebra.Com's Answer #389008 by nerdybill(7384)\"\" \"About 
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y varies directly with x. y =15 when x=4. what is the value of y when x=5
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\n" ); document.write( "When you see \"y varies directly with x\" think:
\n" ); document.write( "y = kx (where k is a constant)
\n" ); document.write( "find this constant by plugging in \"y =15 when x=4\" from the problem:
\n" ); document.write( "15 = k(4)
\n" ); document.write( "15/4 = k
\n" ); document.write( ".
\n" ); document.write( "Now, our equation is:
\n" ); document.write( "y = (15/4)X
\n" ); document.write( "We can now answer:
\n" ); document.write( "what is the value of y when x=5
\n" ); document.write( "y = (15/4)X
\n" ); document.write( "y = (15/4)5
\n" ); document.write( "y = 75/4
\n" ); document.write( "y = 18.75
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\n" ); document.write( "y varies inversely with x y=8 when x=8. what is the value of y when x=4
\n" ); document.write( "When you see \"y varies inversely with x\" think:
\n" ); document.write( "y = k/x (where k is a constant)
\n" ); document.write( "find this constant by plugging in \"y=8 when x=8\" from the problem:
\n" ); document.write( "8 = k/8
\n" ); document.write( "8/8 = k
\n" ); document.write( "1 = k
\n" ); document.write( ".
\n" ); document.write( "Now our equation is:
\n" ); document.write( "y = 1/x
\n" ); document.write( "We can now answer:
\n" ); document.write( "what is the value of y when x=4
\n" ); document.write( "y = 1/x
\n" ); document.write( "y = 1/4
\n" ); document.write( "y = .25\r
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