document.write( "Question 1031509: Solve by substitution:
\n" ); document.write( "3x+5y=16
\n" ); document.write( "5x-7y=-4\r
\n" ); document.write( "\n" ); document.write( "I know the answer is (2,2), because I can solve this by the addition method by multiplying each by the coefficients of x, and solve. Easy Peasy!
\n" ); document.write( "But when I try the substitution method, it all goes straight to huge fractions that don't reduce to 2, by any means. I read this as, take the 1st equation and solve for y, and substitute the y value in the second and solve.
\n" ); document.write( "I am messing up somewhere, please help:) and Thanks! \n" ); document.write( "
Algebra.Com's Answer #646195 by fractalier(6550)\"\" \"About 
You can put this solution on YOUR website!
Yes, you have the right idea, and yes, working a problem like this via substitution is the hard way...but here goes...doing it as you recommend...
\n" ); document.write( "3x+5y=16
\n" ); document.write( "5y = -3x + 16
\n" ); document.write( "y = (-3/5)x + 16/5
\n" ); document.write( "Now substitute this into the second equation and get
\n" ); document.write( "5x - 7((-3/5)x + 16/5) = -4
\n" ); document.write( "5x + (21/5)x - 112/5 = -4
\n" ); document.write( "Multiply everything by 5 and get
\n" ); document.write( "25x + 21x - 112 = -20
\n" ); document.write( "46x - 112 = -20
\n" ); document.write( "46x = 92
\n" ); document.write( "x = 2
\n" ); document.write( "Now plug back in to the first one and get
\n" ); document.write( "3(2) + 5y = 16
\n" ); document.write( "6 + 5y = 16
\n" ); document.write( "5y = 10
\n" ); document.write( "y = 2
\n" ); document.write( "There you are...(2,2) \n" ); document.write( "
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