document.write( "Question 965485: Thelma wants to find the equation of a line that passes through the point (2,2) and is perpendicular to the line y = 1/2 x +5. Which equation best represent Thelma's equation?\r
\n" ); document.write( "\n" ); document.write( "A. y = 2x - 2
\n" ); document.write( "B. y = 1/2 x +1
\n" ); document.write( "C. y = -1/2 x + 3
\n" ); document.write( "D. y = -2x + 6
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Algebra.Com's Answer #590153 by Edwin McCravy(20056) $\"\"$ $\"About$

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document.write( "Those choices all pass through (2,2) so substituing that does no good.\r\n" );
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document.write( "We have to know two things:\r\n" );
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document.write( "1. y = mx+b.  when you see y = ↏x+↏ or y= ↏x-↏ where there are numbers in \r\n" );
document.write( "those boxes that the number in the first box is always the slope.\r\n" );
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document.write( "2. If one line has the slope  then a line perpendicular\r\n" );
document.write( "to it has the slope .  \"We flip it and change its sign\" \r\n" );
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document.write( "[That's because : \r\n" );
document.write( "a. We flip it because the 'rise' on one line becomes a 'run' on a\r\n" );
document.write( "line perpendicular to it and vece-versa.\r\n" );
document.write( "and \r\n" );
document.write( "b. We change the sign because if a line goes uphill to the right \r\n" );
document.write( "it has a positive slope. A line perpendicular to it goes downhill \r\n" );
document.write( "to the right and has a negative slope.] \r\n" );
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document.write( "So we look at  and see that its slope is ,\r\n" );
document.write( "So we flip it and change the sign and get  which simplifies\r\n" );
document.write( "to .  Then we look through the list of choices and find the one\r\n" );
document.write( "that has a  as a coefficient of x.  Then we see that the only choice\r\n" );
document.write( "is D.\r\n" );
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document.write( "Edwin

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