document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1046124>Question 1046124</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A function y=ax^2-4x-c. If the y-int is -3 and the co-ordinates of the vertex is (2,-7), find the value of a.\r<BR>\n" );
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document.write( "Thanks! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #661619 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=661619\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> ax^2-4x-c<BR>\n" );
document.write( "Vertex is (h,k) where h=2 and k=-7<BR>\n" );
document.write( "This is  a(x-h)^2+k<BR>\n" );
document.write( "a(x-2)^2-7 is the function, and when x=0, y=-3 (y-intercept)<BR>\n" );
document.write( "Therefore a(-2)^2-7= -3<BR>\n" );
document.write( "4a-7=-3<BR>\n" );
document.write( "4a=4<BR>\n" );
document.write( "a=1  ANSWER<BR>\n" );
document.write( "Therefore, the function should be (x-2)^2-7 in vertex form or<BR>\n" );
document.write( "x^2-4x-3 in standard form.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=graph%28300%2C200%2C-10%2C10%2C-10%2C10%2Cx%5E2-4x-3%29 ALIGN=MIDDLE  ALT=\"graph%28300%2C200%2C-10%2C10%2C-10%2C10%2Cx%5E2-4x-3%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Another way to check this or to do it is the vertex x component is -b/2a.<BR>\n" );
document.write( "We know the vertex is -(-4)/2a=2 (the 2 is given)<BR>\n" );
document.write( "4/2a=2<BR>\n" );
document.write( "4=4a<BR>\n" );
document.write( "a=1 </SPAN>\n" );
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