document.write( "Question 789054: Please help to solve the use of method of substitution to solve the system of linear equations. 4x-y=3 and 9x-2y=11 \n" ); document.write( "

Algebra.Com's Answer #478705 by rothauserc(4718) $\"\"$ $\"About$

You can put this solution on YOUR website!
we are given two equations in two unknowns
\n" ); document.write( "4x-y = 3
\n" ); document.write( "9x-2y = 11
\n" ); document.write( "solve first equation for y
\n" ); document.write( "-y = 3 -4x
\n" ); document.write( "y = 4x -3
\n" ); document.write( "substitute for y in second equation
\n" ); document.write( "9x -2*(4x -3) = 11
\n" ); document.write( "9x -8x +6 = 11
\n" ); document.write( "x = 5
\n" ); document.write( "now substitute for x in fist equation
\n" ); document.write( "4*5 -y = 3
\n" ); document.write( "20 -y = 3
\n" ); document.write( "y = 17
\n" ); document.write( "now subtitute for x and y in second equation as a check
\n" ); document.write( "9*5 - 2*17 = 11
\n" ); document.write( "45 - 34 = 11
\n" ); document.write( "11 = 11
\n" ); document.write( "so x = 5 and y = 17 answers check
\n" ); document.write( " \n" ); document.write( "

\n" );