document.write( "Question 823880: I need not only answers,but detail solution too
\n" ); document.write( "The points (-4,0), (-3,-6), (-2, -10) and (1,-10) lie on the curve y = \"ax%5E2+%2B+bx+%2B+c\". Find a,
\n" ); document.write( "b and c and hence draw the curve showing clearly the turning point.
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Algebra.Com's Answer #495933 by jsmallt9(3758)\"\" \"About 
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( "\"%28-2%2B1%29%2F2+=+-1%2F2\"
\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, \"y+=+a%28x-h%29%5E2+%2B+k\" for the equation of this parabola. (Then we will transform the equation into standard \"y+=+ax%5E2%2Bbx%2Bc\" form.) In the vertex form the \"h\" and the \"k\" are the x and y coordinates of the vertex. Since we have already found the x-coordinate we can start with:
\n" ); document.write( "\"y+=+a%28x-%28-1%2F2%29%29%5E2+%2B+k\"
\n" ); document.write( "which simplifies to:
\n" ); document.write( "\"y+=+a%28x%2B1%2F2%29%5E2+%2B+k\"

\n" ); document.write( "Next we will substitute in the coordinates of the given points. I'll use (1, -10):
\n" ); document.write( "\"%28-10%29+=+a%28%281%29%2B1%2F2%29%5E2+%2B+k\"
\n" ); document.write( "Simplifying...
\n" ); document.write( "\"-10+=+a%283%2F2%29%5E2+%2B+k\"
\n" ); document.write( "\"-10+=+a%289%2F4%29+%2B+k\"
\n" ); document.write( "\"-10+=+%289%2F4%29a+%2B+k\"
\n" ); document.write( "Solving this for k:
\n" ); document.write( "\"-%289%2F4%29a+-+10+=+k\"

\n" ); document.write( "Now we'll repeat this with another point. I'll use (-3, -6):
\n" ); document.write( "\"%28-6%29+=+a%28%28-3%29%2B1%2F2%29%5E2+%2B+k\"
\n" ); document.write( "Simplifying...
\n" ); document.write( "\"-6+=+a%28-5%2F2%29%5E2+%2B+k\"
\n" ); document.write( "\"-6+=+a%2825%2F4%29+%2B+k\"
\n" ); document.write( "\"-6+=+%2825%2F4%29a+%2B+k\"

\n" ); document.write( "Now we'll substitute, into this equation, the expression we got earlier for k:
\n" ); document.write( "\"-6+=+%2825%2F4%29a+%2B+%28-%289%2F4%29a+-+10%29\"
\n" ); document.write( "With only the \"a\" left, we can solve for it. Simplifying...
\n" ); document.write( "\"-6+=+%2816%2F4%29a+-+10%29\"
\n" ); document.write( "\"-6+=+4a+-+10%29\"
\n" ); document.write( "Adding 10:
\n" ); document.write( "\"4+=+4a%29\"
\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( "\"-%289%2F4%29a+-+10+=+k\"
\n" ); document.write( "\"-%289%2F4%29%281%29+-+10+=+k\"
\n" ); document.write( "\"-9%2F4+-+40%2F4+=+k\"
\n" ); document.write( "\"-49%2F4+=+k\"

\n" ); document.write( "Our vertex form is now complete:
\n" ); document.write( "\"y+=+%281%29%28x%2B1%2F2%29%5E2+%2B+%28-49%2F4%29\"
\n" ); document.write( "which simplifies to:
\n" ); document.write( "\"y+=+%28x%2B1%2F2%29%5E2+%2B+%28-49%2F4%29\"
\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( "\"y+=+%28x%29%5E2%2B2%28x%29%281%2F2%29%2B+%281%2F2%29%5E2+%2B+%28-49%2F4%29\"
\n" ); document.write( "\"y+=+x%5E2%2Bx%2B+1%2F4+%2B+%28-49%2F4%29\"
\n" ); document.write( "\"y+=+x%5E2%2Bx%2B+%28-48%2F4%29\"
\n" ); document.write( "\"y+=+x%5E2%2Bx%2B+%28-12%29\"
\n" ); document.write( "
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