document.write( "Question 1021931: I really need help on vertex forms and standard form parabolas. I understand how to get the vertex but I don't understand when a problem is like this: (x+1)(x-3) and (x+3)^2 -1 \n" ); document.write( "
Algebra.Com's Answer #637627 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
I really need help on vertex forms and standard form parabolas. I understand how to get the vertex but I don't understand when a problem is like this:
\n" ); document.write( "------------------------------------
\n" ); document.write( "y = (x+1)(x-3)
\n" ); document.write( "y = x^2 - 2x - 3
\n" ); document.write( "a = 1 ; b = -2 ; c = -3
\n" ); document.write( "Vertex occurs at x = -b/(2a) = 2/(2*1) = 1
\n" ); document.write( "--------
\n" ); document.write( "f(1) = 1^2 -2*1 - 3 = -4
\n" ); document.write( "--
\n" ); document.write( "Vertex:: (1,-4)
\n" ); document.write( "==========================
\n" ); document.write( "y = (x+3)^2 -1
\n" ); document.write( "y = x^2 + 6x + 8
\n" ); document.write( "a = 1 ; b = 6 ; c = 8
\n" ); document.write( "-----------------
\n" ); document.write( "Vertex at x = -b/(2a) = -6/(2*1) = -3
\n" ); document.write( "f(-3) = (-3+3)^2 - 1 = -1
\n" ); document.write( "-----
\n" ); document.write( "Vertex:: (-3,-1)
\n" ); document.write( "-------------
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
\n" ); document.write( "------------- \n" ); document.write( "
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