document.write( "Question 123204: 3x+y<9 , the < or > signs means equal to or greater or lesser than.
\n" ); document.write( "x-y<7, the > has a line under it. Didn't know how to make it on here.
\n" ); document.write( "x>0,\r
\n" ); document.write( "\n" ); document.write( "Which of the following points satisfy the inequalities?
\n" ); document.write( " (2,5), ( 0,9), (3,-2) or (-1,0)
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Algebra.Com's Answer #90407 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
The best way is to plot these
\n" ); document.write( "(1) \"3x+%2B+y+%3C+9\"
\n" ); document.write( "(2) \"x+-+y+%3C+7\"
\n" ); document.write( "(3) \"x+%3E+0\"
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\n" ); document.write( "Find \"y\" in terms of \"x\"
\n" ); document.write( "(1) \"3x+%2B+y+%3C+9\"
\n" ); document.write( "\"y+%3C+-3x+%2B+9\"
\n" ); document.write( "(2) \"x+-+y+%3C+7\"
\n" ); document.write( "\"-y+%3C+-x+%2B+7\"
\n" ); document.write( "multiply both sides by \"-1\" and reverse the < sign
\n" ); document.write( "\"y+%3E+x+-+7\"
\n" ); document.write( "(3) \"x+%3E0\" No \"y\" involved here. This is saying that \"x\"
\n" ); document.write( "can never be \"0\" or negative. It's domain is the right half of
\n" ); document.write( "the graph
\n" ); document.write( "I'll do a plot of
\n" ); document.write( "\"y+%3C+-3x+%2B+9\" and
\n" ); document.write( "\"y+%3E+x+-+7\"
\n" ); document.write( " \"+graph%28+600%2C+600%2C+-2%2C+30%2C+-15%2C+15%2C+-3x+%2B+9%2Cx+-+7%29\"
\n" ); document.write( "The solution is the little triangular area bounded by the \"y\" axis
\n" ); document.write( "and the lines. Now see which points are in that area
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\n" ); document.write( "(2,5) looks to be just outside, and it fails (1) because
\n" ); document.write( "\"y+%3C+-3x+%2B+9\"
\n" ); document.write( "\"5+%3C+%28-3%29%2A2+%2B+9\"
\n" ); document.write( "\"5+%3C+-6+%2B+9\"
\n" ); document.write( "\"5+%3C+3\" This is clearly not true
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\n" ); document.write( "(0,9) This looks like it might be in the area, but it fails (1) also
\n" ); document.write( "\"y+%3C+-3x+%2B+9\"
\n" ); document.write( "\"9+%3C+%28-3%29%2A0+%2B+9\"
\n" ); document.write( "\"9+%3C+9\" This is clearly not true also
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\n" ); document.write( "(3,-2) This fails in the area
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\n" ); document.write( "(-1,0) \"x\" can't be negative, as I said, and it is
\n" ); document.write( "also clearly outside the area
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\n" ); document.write( "So, only (3,-2) satisfies the inequalities answer
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