document.write( "Question 823880: I need not only answers,but detail solution too
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document.write( "The points (-4,0), (-3,-6), (-2, -10) and (1,-10) lie on the curve y = . Find a,
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document.write( "b and c and hence draw the curve showing clearly the turning point. \n" );
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Algebra.Com's Answer #495933 by jsmallt9(3758)![]() ![]() ![]() You can put this solution on YOUR website! A key to a quick solution is noticing that the points (-2, -10) and (1, -10) have the same y-coordinate. Because of the symmetry of parabolas, these two points tells us that the axis of symmetry and the vertex are halfway between -2 and 1: \n" ); document.write( " \n" ); document.write( "So the x-coordinate of the vertex is -1/2. \n" ); document.write( "We will use this to build the vertex form, \n" ); document.write( " \n" ); document.write( "which simplifies to: \n" ); document.write( " \n" ); document.write( "Next we will substitute in the coordinates of the given points. I'll use (1, -10): \n" ); document.write( " \n" ); document.write( "Simplifying... \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Solving this for k: \n" ); document.write( " \n" ); document.write( "Now we'll repeat this with another point. I'll use (-3, -6): \n" ); document.write( " \n" ); document.write( "Simplifying... \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Now we'll substitute, into this equation, the expression we got earlier for k: \n" ); document.write( " \n" ); document.write( "With only the \"a\" left, we can solve for it. Simplifying... \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Adding 10: \n" ); document.write( " \n" ); document.write( "Dividing by 4: \n" ); document.write( "1 = a \n" ); document.write( "Now we can use this to find k: \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Our vertex form is now complete: \n" ); document.write( " \n" ); document.write( "which simplifies to: \n" ); document.write( " \n" ); document.write( "With h = -1/2 and k = -49/4, the vertex/\"turning point\" is (-1/2, -49/4). \n" ); document.write( "All that's left is to transform this into standard form. Simplifying... \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " |