document.write( "Question 537186: Hello, I am trying to figure out how to solve a system by the method of substitution. I have two problems in which I am having trouble with.\r
\n" ); document.write( "\n" ); document.write( "1) {x+3y=8
\n" ); document.write( " {y= 2x-9\r
\n" ); document.write( "\n" ); document.write( "and \r
\n" ); document.write( "\n" ); document.write( "2) {5x+2y=0
\n" ); document.write( " {x-3y=0\r
\n" ); document.write( "\n" ); document.write( "I'm confused on how to begin and the proper way to solve the problem, thank you for your help.
\n" ); document.write( "

Algebra.Com's Answer #352749 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
To solve a system of two linear equations by substitution, you solve for one of the variables in one equation and substitute the expression found in the other.
\n" ); document.write( "Let's see how it works for your problems.
\n" ); document.write( "1) \"x%2B3y=8\"
\n" ); document.write( "\"y=+2x-9\"
\n" ); document.write( "Half of the work is already done for you because \"y=+2x-9\" is already \"solved\" for \"y\", so you just substitute \"2x-9\" for \"y\" in the other equation.
\n" ); document.write( "\"x%2B3%282x-9%29=8\"
\n" ); document.write( "Multiply (apply distributive property)
\n" ); document.write( "\"x%2B6x-27=8\"
\n" ); document.write( "Collect like terms (distributive property backwards, adding apples to apples and x's to x's)
\n" ); document.write( "\"7x-27=8\"
\n" ); document.write( "Add 27 to both sides
\n" ); document.write( "\"7x=8%2B27\"-->\"7x=35\"
\n" ); document.write( "Divide both sides by 7
\n" ); document.write( "\"x=5\"
\n" ); document.write( "Then go back to find y
\n" ); document.write( "\"y=2x-9=2%2A5-9=1\"
\n" ); document.write( "So the answer is x=5 with y=1, usually expressed as the pair (5, 1).
\n" ); document.write( "2) \"5x%2B2y=0\"
\n" ); document.write( " \"x-3y=0\"
\n" ); document.write( "You need to solve for x or for y one of the two equations I would go with x in the second one:
\n" ); document.write( "\"x-3y=0\"-->\"x=3y\"
\n" ); document.write( "Then substitute in the first equation
\n" ); document.write( "\"5%283y%29%2B2y=0\"-->\"15y%2B2y=0\"-->\"15y=0\"-->\"y=0\"
\n" ); document.write( "and then \"x=3y=3%2A0=0\"
\n" ); document.write( "The solution is (0, 0).
\n" ); document.write( "
\n" );