document.write( "Question 369574: the variable x and y vary directly. Use the given values to write an equation that relatesx and y.
\n" ); document.write( " 1) x=3, y=15\r
\n" ); document.write( "\n" ); document.write( " 2) x=4, y=-16\r
\n" ); document.write( "\n" ); document.write( "plz i need help asap \n" ); document.write( "
Algebra.Com's Answer #263367 by Alan3354(69443)\"\" \"About 
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the variable x and y vary directly. Use the given values to write an equation that relatesx and y.
\n" ); document.write( " 1) x=3, y=15\r
\n" ); document.write( "\n" ); document.write( " 2) x=4, y=-16
\n" ); document.write( "------------------
\n" ); document.write( "2 points are given, (3,15) and (4,-16)
\n" ); document.write( "Find the eqn of the straight line that passes thru them.
\n" ); document.write( "Slope m = diffy/diffx = -31/1 = -31
\n" ); document.write( "Use the slope and either point to find b, the y-intercept
\n" ); document.write( "y = mx + b
\n" ); document.write( "15 = 3*(-31) + b
\n" ); document.write( "b = 108
\n" ); document.write( "--> y = -31x + 108
\n" ); document.write( "That's all.
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