document.write( "Question 1187647: find the equation of a parabola with vertex on the line y=2x, axis parallel to the x-axis and passing through (3/2, 1) and (3,4).\r
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Algebra.Com's Answer #818689 by greenestamps(13200)![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "The given information is unusual, so initially we don't have a good idea of where to go with the problem. So we do the only thing we can -- write the general form of the equation and use each the two given points in that equation to see what it gives us. \n" ); document.write( "The vertex is on the line y=2x, so we can call the coordinates of the vertex (a,2a). Then the vertex form of the equation of a parabola parallel to the x-axis with vertex (a,2a) is \n" ); document.write( " \n" ); document.write( "Plug in (x,y)=(1.5,1) and (x,y)=(3,4) to get two equations in a and p: \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Subtract [1] from [2]: \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Substitute [3] in [2]: \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "There will be two parabolas that satisfy the given conditions. \n" ); document.write( "(1) a=3.5; 4p=10-8a=-18; 2a=7 \n" ); document.write( " \n" ); document.write( "(2) a=1; 4p=10-8a=2; 2a=2 \n" ); document.write( " \n" ); document.write( "Here is a graph of the two parabolas, one with vertex (1,2) and the other with vertex (3.5,7) and both passing through the points (1.5,1) and (3,4) \n" ); document.write( " |