document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=88766>Question 88766</A>: <I><SPAN STYLE=\"word-break: break-all;\"> How do I enter this problem to work it?\r<BR>\n" );
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document.write( "Use formula x=-b/2a to find the coordinates of the vertex for the parabola defined by the quadratic function f(x)=2x^2+4x-15. Substitute this value into the f(x) to find the y coordinate of the vertex. Plot  two points to the left and right of the vertex. Do the graph of the parabola.    HELP!!! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #64519 by </B><A HREF=/tutors/aboutme.mpl?userid=Earlsdon><B>Earlsdon(6294)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Earlsdon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=64519\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Find the vertex of the parabola defined by:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=f%28x%29+=+2x%5E2%2B4x-15 ALIGN=MIDDLE  ALT=\"f%28x%29+=+2x%5E2%2B4x-15\"   DISABLED_style= \"max-width:90%; height:auto;\" > Compare this with the general form:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=f%28x%29+=+ax%5E2%2Bbx%2Bc ALIGN=MIDDLE  ALT=\"f%28x%29+=+ax%5E2%2Bbx%2Bc\"   DISABLED_style= \"max-width:90%; height:auto;\" >...and you can see that: a = 2, b = 4, and c = -15<BR>\n" );
document.write( "Now substitute a and b into the formula for the x-coordinate of the vertex:<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-b%2F2a ALIGN=MIDDLE  ALT=\"-b%2F2a\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+-4%2F2%282%29 ALIGN=MIDDLE  ALT=\"x+=+-4%2F2%282%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+-4%2F4 ALIGN=MIDDLE  ALT=\"x+=+-4%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+-1 ALIGN=MIDDLE  ALT=\"x+=+-1\"   DISABLED_style= \"max-width:90%; height:auto;\" > This is the x-coordinate of the vertex.  Substitute this value of x into the given quadratic equation and solve for f(x), this is the same as the y-coordinate.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=f%28-1%29+=+2%28-1%29%5E2%2B4%28-1%29-15 ALIGN=MIDDLE  ALT=\"f%28-1%29+=+2%28-1%29%5E2%2B4%28-1%29-15\"   DISABLED_style= \"max-width:90%; height:auto;\" > Evaluate.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=f%28-1%29+=+2-4-15 ALIGN=MIDDLE  ALT=\"f%28-1%29+=+2-4-15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=f%28-1%29+=+-17 ALIGN=MIDDLE  ALT=\"f%28-1%29+=+-17\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The coordinates of the vertex are:<BR>\n" );
document.write( "(-1, -17)...and the equation of the line of symmetry is:<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+-1 ALIGN=MIDDLE  ALT=\"x+=+-1\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The graph looks like this:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=graph%28400%2C400%2C-5%2C5%2C-20%2C5%2C2x%5E2%2B4x-15%29 ALIGN=MIDDLE  ALT=\"graph%28400%2C400%2C-5%2C5%2C-20%2C5%2C2x%5E2%2B4x-15%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "To plot two points to the left and to the right of the vertex (line of symmetry), choose four values of x-coordinate, such as:<BR>\n" );
document.write( "x = 0<BR>\n" );
document.write( "x = -2<BR>\n" );
document.write( "x = 1<BR>\n" );
document.write( "x = -3<BR>\n" );
document.write( "and for each one of these, find the corresponding y-coordinate (f(x)) and these will give you the coordinates of the four points.<BR>\n" );
document.write( "I'll do one and you can finish the rest.<BR>\n" );
document.write( "Substitute x = -3<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=f%28-3%29+=+2%28-3%29%5E2%2B4%28-3%29-15 ALIGN=MIDDLE  ALT=\"f%28-3%29+=+2%28-3%29%5E2%2B4%28-3%29-15\"   DISABLED_style= \"max-width:90%; height:auto;\" > Evaluate.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=f%28x%29+=+2%289%29%2B%28-12%29-15 ALIGN=MIDDLE  ALT=\"f%28x%29+=+2%289%29%2B%28-12%29-15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=f%28x%29+=+18-12-15 ALIGN=MIDDLE  ALT=\"f%28x%29+=+18-12-15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=f%28x%29+=+-9 ALIGN=MIDDLE  ALT=\"f%28x%29+=+-9\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The coordinates of this point are: (-3, -9) </SPAN>\n" );
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