document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=125029>Question 125029</A>: <I><SPAN STYLE=\"word-break: break-all;\"> This entire lesson revolves around the 3 step principle of:<BR>\n" );
document.write( "assigning a variable<BR>\n" );
document.write( "writing a sentence placing the demands on the variable<BR>\n" );
document.write( "solving the equation.<BR>\n" );
document.write( "We need a usable formula that will work in all these cases!<BR>\n" );
document.write( "THANK YOU!!!\r<BR>\n" );
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document.write( "Here's the question:<BR>\n" );
document.write( "Two years ago a father was four times as old as his son.  Three years from now the father will be only three times as old as the son.  How old is each now? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #91687 by </B><A HREF=/tutors/aboutme.mpl?userid=edjones><B>edjones(8007)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=edjones><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=edjones><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=91687\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Define the variables any way you want, as long as you are consistent, and then solve the equation. The one that works best with your brain is the best for you. This one is best for mine:<BR>\n" );
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document.write( "Let x be the son's age 2 yrs ago.<BR>\n" );
document.write( "Let y be the father's age 2 yrs ago.<BR>\n" );
document.write( "Both these variables are consistent (2 yrs ago). You could have made them equal to the present or three yrs from now. You would have had different equations in those cases but the answers (if ou did it right) would have been the same.<BR>\n" );
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document.write( "A) y=4x 2 yrs ago<BR>\n" );
document.write( "B) y+5=3(x+5) 3 yrs from now.<BR>\n" );
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document.write( "Substitute 4x for y in B):<BR>\n" );
document.write( "4x+5=3x+15<BR>\n" );
document.write( "4x-3x+5-5=3x-3x+15-5<BR>\n" );
document.write( "x=10<BR>\n" );
document.write( "A) y=4*10<BR>\n" );
document.write( "y=40<BR>\n" );
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document.write( "So the son is now 12 and the father 42.<BR>\n" );
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document.write( "Ed\r<BR>\n" );
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document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );