document.write( "Question 477473: Solve each system of equations by using substitution.\r
\n" ); document.write( "\n" ); document.write( " $\"+8x+%2B+9y+=+9+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"+3x+-+5y+=+20+\"$ \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "I've multiplied the bottom equation by 3 and got 9x - 15y = 60, but it isn't going to be correct because 8x - 9x = -x so the x hasn't been eliminated. I don't know what to do about it. The rest of the problem made no sense because the numbers were too high after I plugged them in. I got -x + -6 = -51 then divided that by -6 which got me 8.5. I didn't know what to do with the -x so I just ignored it bu I don't think that's right. Any solutions? \n" ); document.write( "

Algebra.Com's Answer #327248 by ewatrrr(24785) $\"\"$ $\"About$

You can put this solution on YOUR website!

 
\n" );
document.write( "Hi,
\n" );
document.write( "Solve each system of equations by using substitution.
\n" );
document.write( "using Substitution
\n" );
document.write( " 8x + 9y = 9 OR   y = (-8/9)x + 1
\n" );
document.write( " 3x - 5[(-8/9)x + 1] = 20
\n" );
document.write( " 3x + 40/9x - 5 = 20
\n" );
document.write( " 27x + 40x - 45 = 180
\n" );
document.write( "        67x = 225
\n" );
document.write( "          x = 225/67  and y = (-8/9)225/67 + 1 = -1.9851
\n" );
document.write( "using Elimination 
\n" );
document.write( " 8x  +  9y = 9
\n" );
document.write( "27/5x - 9y = 36  |Recommend multiplying thru with 9/5 to eliminate y
\n" );
document.write( "    67/5x = 45
\n" );
document.write( "        x = 225/67 etc   \n" );
document.write( "

\n" );