document.write( "Question 536435: solve by the substitution method 3x-9y=69 5x+25=y. the solution \n" ); document.write( "
Algebra.Com's Answer #352343 by Maths68(1474)\"\" \"About 
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\"3x-9y=69\".............(1)
\n" ); document.write( "\"5x%2B25=y\"..............(2)
\n" ); document.write( "Put the value of y in (1)
\n" ); document.write( "\"3x-9%285x%2B25%29=69\"
\n" ); document.write( "\"3x-45x-225=69\"
\n" ); document.write( "\"-42x=69%2B225\"
\n" ); document.write( "\"-42x=294\"
\n" ); document.write( "Divide by -42 both sides
\n" ); document.write( "\"-42%2F-42x=294%2F-42\"
\n" ); document.write( "\"cross%28-42%29%2Fcross%28-42%29x=-cross%28294%29%2Fcross%2842%29\"
\n" ); document.write( "\"x=-7\"
\n" ); document.write( "Put the value of x in (1)
\n" ); document.write( "\"3x-9y=69\"
\n" ); document.write( "\"3%28-7%29-9y=69\"
\n" ); document.write( "\"-21-9y=69\"
\n" ); document.write( "\"-9y=69%2B21\"
\n" ); document.write( "\"-9y=90\"
\n" ); document.write( "Divide by -9 both sides
\n" ); document.write( "\"-9y%2F-9=90%2F-9\"
\n" ); document.write( "\"cross%28-9%29y%2Fcross%28-9%29=-cross%2890%29%2Fcross%289%29\"
\n" ); document.write( "\"y=-10\"\r
\n" ); document.write( "\n" ); document.write( "x,y=-7,-10\r
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\n" ); document.write( "\n" ); document.write( "Check
\n" ); document.write( "=====
\n" ); document.write( "Put the values of x and y in (1)
\n" ); document.write( "\"3x-9y=69\".............(1)
\n" ); document.write( "\"3%28-7%29-9%28-10%29=69\"
\n" ); document.write( "\"-21%2B90=69\"
\n" ); document.write( "\"69=69\"
\n" ); document.write( "Put the values of x and y in (2)
\n" ); document.write( "\"5x%2B25=y\"..............(2)
\n" ); document.write( "\"5%28-3%29%2B25=-10\"
\n" ); document.write( "\"-15%2B25=-10\"
\n" ); document.write( "\"-10=-10\"\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
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