document.write( "Question 1148201: How do i make a quadratic equation from vertex point (4,-3) and point (6,-1)? \n" ); document.write( "
Algebra.Com's Answer #769559 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
The general form is \"+f%28x%29+=++a%2Ax%5E2+%2B+b%2Ax+%2B+c+\"
\n" ); document.write( "The y-component of ( 6, -1 ) is greater than the
\n" ); document.write( "y-component of the vertex, so I know the vertex is
\n" ); document.write( "a minimum ( just an observation )
\n" ); document.write( "----------------------------------------------------
\n" ); document.write( "( 4, -3 )
\n" ); document.write( "\"+-3+=+a%2A4%5E2+%2B+b%2A4+%2B+c+\"
\n" ); document.write( "(1) \"+-3+=+16a+%2B+4b+%2B+c+\"
\n" ); document.write( "------------------------------
\n" ); document.write( "For the vertex:
\n" ); document.write( "\"+-b%2F%282a%29+=+4+\"
\n" ); document.write( "(2) \"+b+=+-8a+\"
\n" ); document.write( "------------------------
\n" ); document.write( "( 6, -1 )
\n" ); document.write( "\"+-1+=+a%2A6%5E2+%2B+b%2A6+%2B+c+\"
\n" ); document.write( "(3) \"+-1+=+36a+%2B+6b+%2B+c+\"
\n" ); document.write( "-------------------------------
\n" ); document.write( "You have 3 equation with 3 unknowns, so
\n" ); document.write( "it's solvable
\n" ); document.write( "-------------------------------
\n" ); document.write( "Plug (2) into (1) and (3)
\n" ); document.write( "(1) \"+16a+%2B+4%2A%28+-8a+%29+%2B+c+%2B+3+=+0+\"
\n" ); document.write( "(1) \"+16a+-+32a+%2B+c+%2B+3+=+0+\"
\n" ); document.write( "(1) \"+-16a+%2B+c+%2B+3+=+0+\"
\n" ); document.write( "--------------------------------
\n" ); document.write( "(3) \"+36a+%2B+6%2A%28+-8a+%29+%2B+c+%2B+1+=+0+\"
\n" ); document.write( "(3) \"+-12a+%2B+c+%2B+1+=+0+\"
\n" ); document.write( "---------------------------------------
\n" ); document.write( "Subtract (1) from (3)
\n" ); document.write( "(3) \"+-12a+%2B+c+%2B+1+=+0+\"
\n" ); document.write( "(1) \"+16a+-+c+-+3+=+0+\"
\n" ); document.write( "------------------------------
\n" ); document.write( "\"+4a+-+2+=+0+\"
\n" ); document.write( "\"+4a+=+2+\"
\n" ); document.write( "\"+a+=+1%2F2+\"
\n" ); document.write( "and
\n" ); document.write( "(2) \"+b+=+-8a+\"
\n" ); document.write( "(2) \"+b+=+-4+\"
\n" ); document.write( "and
\n" ); document.write( "(3) \"+-12a+%2B+c+%2B+1+=+0+\"
\n" ); document.write( "(3) \"+-12%2A%28+1%2F2%29+%2B+c+%2B+1+=+0+\"
\n" ); document.write( "(3) \"+-6+%2B+c+%2B+1+=+0+\"
\n" ); document.write( "(3) \"+c+=+5+\"
\n" ); document.write( "----------------------------------
\n" ); document.write( "The equation is:
\n" ); document.write( "\"+y+=+%281%2F2%29%2Ax%5E2+-+4x+%2B+5+\"
\n" ); document.write( "----------------------------------
\n" ); document.write( "check:
\n" ); document.write( "( 4, -3 )
\n" ); document.write( "\"+-3+=+%281%2F2%29%2A4%5E2+-+4%2A4+%2B+5+\"
\n" ); document.write( "\"+-3+=+8+-+16+%2B+5+\"
\n" ); document.write( "\"+-3+=+-3+\"
\n" ); document.write( "OK
\n" ); document.write( "and
\n" ); document.write( "( 6, -1 )
\n" ); document.write( "\"+-1+=+%281%2F2%29%2A6%5E2+-4%2A6+%2B+5+\"
\n" ); document.write( "\"+-1+=+18+-+24+%2B+5+\"
\n" ); document.write( "\"+-1+=+-1+\"
\n" ); document.write( "OK
\n" ); document.write( "Here's the plot:
\n" ); document.write( "\"+graph%28+400%2C+400%2C+-10%2C+10%2C+-10%2C+10%2C+%281%2F2%29%2Ax%5E2+-+4x+%2B+5+%29+\"
\n" ); document.write( "Looks OK
\n" ); document.write( "
\n" ); document.write( "
\n" );