document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=194785>Question 194785</A>: <I><SPAN STYLE=\"word-break: break-all;\"> i have to write an equation of the line that is tangent to the circle at that point:\r<BR>\n" );
document.write( "\n" );
document.write( "x^2+y^2=50; (-7,1) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #146117 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=146117\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> First, answer the question: \"Is the point (-7,1)<BR>\n" );
document.write( "on the circle?\"<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%5E2+%2B+y%5E2+=+50 ALIGN=MIDDLE  ALT=\"x%5E2+%2B+y%5E2+=+50\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28-7%29%5E2+%2B+1%5E2+=+50 ALIGN=MIDDLE  ALT=\"%28-7%29%5E2+%2B+1%5E2+=+50\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=49+%2B+1+=+50 ALIGN=MIDDLE  ALT=\"49+%2B+1+=+50\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=50+=+50 ALIGN=MIDDLE  ALT=\"50+=+50\"   DISABLED_style= \"max-width:90%; height:auto;\" > Yes<BR>\n" );
document.write( "The center of the circle is the origin.<BR>\n" );
document.write( "Next find the equation of the line  that<BR>\n" );
document.write( "contains the points (0,0) and (-7,1)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28y+-+1%29+%2F+%28x+-+%28-7%29%29+=+%280+-+1%29+%2F+%280+-+%28-7%29%29 ALIGN=MIDDLE  ALT=\"%28y+-+1%29+%2F+%28x+-+%28-7%29%29+=+%280+-+1%29+%2F+%280+-+%28-7%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28y+-+1%29+%2F+%28x+%2B+7%29+=+-1+%2F+7 ALIGN=MIDDLE  ALT=\"%28y+-+1%29+%2F+%28x+%2B+7%29+=+-1+%2F+7\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7%2A%28x+%2B+7%29 ALIGN=MIDDLE  ALT=\"7%2A%28x+%2B+7%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7%2A%28y+-+1%29+=+-%28x+%2B+7%29 ALIGN=MIDDLE  ALT=\"7%2A%28y+-+1%29+=+-%28x+%2B+7%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7y+-+7+=+-x+-+7 ALIGN=MIDDLE  ALT=\"7y+-+7+=+-x+-+7\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7y+=+-x ALIGN=MIDDLE  ALT=\"7y+=+-x\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+-%281%2F7%29%2Ax ALIGN=MIDDLE  ALT=\"y+=+-%281%2F7%29%2Ax\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "This is of the form <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+mx ALIGN=MIDDLE  ALT=\"y+=+mx\"   DISABLED_style= \"max-width:90%; height:auto;\" >, and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m ALIGN=MIDDLE  ALT=\"m\"   DISABLED_style= \"max-width:90%; height:auto;\" > is the slope<BR>\n" );
document.write( "Any line perpendicular to this one will have slope<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-%281%2Fm%29 ALIGN=MIDDLE  ALT=\"-%281%2Fm%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >, in this case, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-%281%2F%28-%281%2F7%29%29%29+=+7 ALIGN=MIDDLE  ALT=\"-%281%2F%28-%281%2F7%29%29%29+=+7\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "So, the line tangent to the circle at (-7,1) will have <BR>\n" );
document.write( "slope = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7 ALIGN=MIDDLE  ALT=\"7\"   DISABLED_style= \"max-width:90%; height:auto;\" >.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28y+-+1%29+%2F+%28x+-+%28-7%29%29+=+7 ALIGN=MIDDLE  ALT=\"%28y+-+1%29+%2F+%28x+-+%28-7%29%29+=+7\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+-+1+=+7%2A%28x+%2B+7%29 ALIGN=MIDDLE  ALT=\"y+-+1+=+7%2A%28x+%2B+7%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+-+1+=+7x+%2B+49 ALIGN=MIDDLE  ALT=\"y+-+1+=+7x+%2B+49\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+7x+%2B+50 ALIGN=MIDDLE  ALT=\"y+=+7x+%2B+50\"   DISABLED_style= \"max-width:90%; height:auto;\" > answer<BR>\n" );
document.write( "I'll plot the circle and the line<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+graph%28+500%2C+500%2C+-60%2C+60%2C+-60%2C+60%2C+sqrt%2850+-+x%5E2%29%2C+-sqrt%2850+-+x%5E2%29%2C+7x+%2B+50%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" >  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );