document.write( "Question 1043466: if the graph of y=x²+mx+n passes through the points (1,12) and (3,28), what is the value of the produce mn? \n" ); document.write( "
Algebra.Com's Answer #658667 by ankor@dixie-net.com(22740)\"\" \"About 
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if the graph of y=x²+mx+n passes through the points (1,12) and (3,28), what is the value of the product mn?
\n" ); document.write( ":
\n" ); document.write( "using the form ax^2 + bx + c = y,
\n" ); document.write( "a = 1; b = m; c = n
\n" ); document.write( "points
\n" ); document.write( "x = 1; y = 12
\n" ); document.write( "1^2 + 1m + n = 12
\n" ); document.write( "m + n = 12 - 1
\n" ); document.write( "m + n = 11
\n" ); document.write( ":
\n" ); document.write( "points:
\n" ); document.write( "x = 3; y = 28
\n" ); document.write( "3^2 + 3m + n = 28
\n" ); document.write( "9 + 3m + n = 28
\n" ); document.write( "3m + n = 28 - 9
\n" ); document.write( "3m + n = 19
\n" ); document.write( ":
\n" ); document.write( "Use elimination with these two equations
\n" ); document.write( "3m + n = 19
\n" ); document.write( " m + n = 11
\n" ); document.write( "-------------subtraction eliminates n, find m
\n" ); document.write( "2m = 8
\n" ); document.write( "m = 8/2
\n" ); document.write( "m = 4
\n" ); document.write( ":
\n" ); document.write( "find n using the equation: m + n = 11, m=4
\n" ); document.write( "n = 11 -4
\n" ); document.write( "n = 7
\n" ); document.write( ":
\n" ); document.write( "the equation for these points
\n" ); document.write( "y = x^2 + 4x + 7
\n" ); document.write( ":
\n" ); document.write( "\"what is the value of the product mn?\" Obviously it's 28
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