document.write( "Question 408915: Tell whether the lines for the pair of equations are parallel, perpendicular, or neither.
\n" ); document.write( "y = (-1/3)x – 5
\n" ); document.write( "-18x + 6y = 21
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Algebra.Com's Answer #287982 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
\"y+=+%28-1%2F3%29x+%96+5\"...this is the slope-intercept form and we can say that slope \"m=%28-1%2F3%29%7D%7D+and+y-intercept+is+%7B%7B%7B-5\"\r
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\n" ); document.write( "\n" ); document.write( "\"-18x+%2B+6y+=+21\"...write this equation in the slope-intercept form too\r
\n" ); document.write( "\n" ); document.write( "\"6y+=18x+%2B+21\"\r
\n" ); document.write( "\n" ); document.write( "\"6y%2F6+=18x%2F6+%2B+21%2F6\"\r
\n" ); document.write( "\n" ); document.write( "\"y+=3x+%2B+3.5\".........we can say that slope \"m=3%7D%7D+and+y-intercept+is+%7B%7B%7B3.5\"\r
\n" ); document.write( "\n" ); document.write( "so the slopes of our lines are \"m=%28-1%2F3%29%7D%7D+and+%7B%7B%7Bm=3%7D%7D%0D%0A%0D%0AIf+%7B%7B%7B2\" lines are \"parallel\" they have the \"same\" slope; evidently, these two lines are \"not\" \"parallel\".\r
\n" ); document.write( "\n" ); document.write( "If they are \"perpendicular\", their slopes \"multiply\" to get \"-1\"; \r
\n" ); document.write( "\n" ); document.write( "so \"m1+=+-1%2Fm2\"\r
\n" ); document.write( "\n" ); document.write( "let's check it:\r
\n" ); document.write( "\n" ); document.write( "\"-1%2F3+=+-1%2F3\".........they are \"perpendicular\"\r
\n" ); document.write( "\n" ); document.write( "let's see their graph:\r
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\n" ); document.write( "\n" ); document.write( "\"+graph%28+500%2C+500%2C+-10%2C+10%2C+-10%2C+10%2C+3x%2B3.5%2C+-0.33x-5%29+\"\r
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