document.write( "Question 62125This question is from textbook beginning algebra
\n" ); document.write( ": This chap is asking to solve the system of equation using subsititution method but I keep getting the wrong ans.\r
\n" ); document.write( "\n" ); document.write( "9. 2x+y=5
\n" ); document.write( " x+3y=0 the book ans is (3,-1)\r
\n" ); document.write( "\n" ); document.write( "11. 2x+y=3
\n" ); document.write( " 2y=-4x+6 the book ans is (Many solutions)\r
\n" ); document.write( "\n" ); document.write( "13. x-y=3
\n" ); document.write( " 3y=x the book ans is (9/2,3/2)\r
\n" ); document.write( "\n" ); document.write( "15. 2x+y=-4
\n" ); document.write( " x-2y=-7 the book ans is (-3,2)\r
\n" ); document.write( "\n" ); document.write( "17. 4x+y=5
\n" ); document.write( " x-3=0\r
\n" ); document.write( "\n" ); document.write( "I am having problem solving using the substitution method. PLEASE HELP ME! \n" ); document.write( "

Algebra.Com's Answer #42918 by Earlsdon(6294) $\"\"$ $\"About$

You can put this solution on YOUR website!
Solve by substitution:
\n" ); document.write( "(9)
\n" ); document.write( " $\"2x%2By+=+5\"$
\n" ); document.write( " $\"x%2B3y+=+0\"$ Rewrite this as: $\"x+=+-3y\"$ and substitute for x in the 1st equation.
\n" ); document.write( " $\"2%28-3y%29%2By+=+5\"$ Solve for y.
\n" ); document.write( " $\"-6y%2By+=+5\"$
\n" ); document.write( " $\"-5y+=+5\"$
\n" ); document.write( " $\"y+=+-1\"$ To find x, use: $\"x+=+-3y\"$
\n" ); document.write( " $\"x+=+-3%28-1%29\"$
\n" ); document.write( " $\"x+=+3\"$ \r
\n" ); document.write( "\n" ); document.write( "Solution is: (3, -1)\r
\n" ); document.write( "\n" ); document.write( "(11)
\n" ); document.write( " $\"2x%2By+=+3\"$ Rewrite as: $\"y+=+-2x%2B3\"$ and substitute for y in the 2nd equation.
\n" ); document.write( " $\"2y+=+-4x%2B6\"$
\n" ); document.write( " $\"2%28-2x%2B3%29+=+-4x%2B6\"$ Simplify and solve for y.
\n" ); document.write( " $\"-4x%2B6+=+-4x%2B6\"$ Add 4x to both sides.
\n" ); document.write( " $\"6+=+6\"$ The two equations represent the same line so there are an infinite number of solutions.\r
\n" ); document.write( "\n" ); document.write( "(13)
\n" ); document.write( " $\"x-y+=+3\"$
\n" ); document.write( " $\"3y+=+x\"$ Substitute this for x in the 1st equation and solve for y.
\n" ); document.write( " $\"3y-y+=+3\"$
\n" ); document.write( " $\"2y+=+3\"$
\n" ); document.write( " $\"y+=+3%2F2\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x+=+3y\"$ Substitute $\"y+=+3%2F2\"$
\n" ); document.write( " $\"x+=+3%283%2F2%29\"$
\n" ); document.write( " $\"x+=+9%2F2\"$ \r
\n" ); document.write( "\n" ); document.write( "Solution is: (9/2, 3/2)\r
\n" ); document.write( "\n" ); document.write( "(15)
\n" ); document.write( " $\"2x%2By+=+-4\"$
\n" ); document.write( " $\"x-2y+=+-7\"$ Rewrite this as: $\"x+=+2y-7\"$ and substitute for x in the 1st equation.
\n" ); document.write( " $\"2%282y-7%29%2By+=+-4\"$ Simplify and solve for y.
\n" ); document.write( " $\"4y-14%2By+=+-4\"$
\n" ); document.write( " $\"5y-14+=+-4\"$
\n" ); document.write( " $\"5y+=+10\"$
\n" ); document.write( " $\"y+=+2\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x+=+2y-7\"$ Substitute $\"y+=+2\"$ and solve for x.
\n" ); document.write( " $\"x+=+2%282%29-7\"$
\n" ); document.write( " $\"x+=+-3\"$ \r
\n" ); document.write( "\n" ); document.write( "The solution is: (-3, 2)\r
\n" ); document.write( "\n" ); document.write( "(17)
\n" ); document.write( " $\"4x%2By+=+5\"$
\n" ); document.write( " $\"x-3+=+0\"$ Rewrite this as: $\"x+=+3\"$ and substitute for x in the 1st equation and solve for y.
\n" ); document.write( " $\"4%283%29%2By+=+5\"$
\n" ); document.write( " $\"12%2By+=+5\"$
\n" ); document.write( " $\"y+=+-7\"$ \r
\n" ); document.write( "\n" ); document.write( "The solution is: (3, -7)\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );