document.write( "Question 201803: explain why the line x=4 is a veritcal line. \n" ); document.write( "

Algebra.Com's Answer #152043 by RAY100(1637) $\"\"$ $\"About$

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Very good question. MOST people have a great deal of difficulty with vertical and horizontal lines.
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\n" ); document.write( " In short, Vertical lines have form,,,x=#
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\n" ); document.write( ",,,,,,,,,,,,,Horizontal lines have form,,,,y=#
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\n" ); document.write( "Remember general linear equations have form, y = mx +b
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\n" ); document.write( "Horizontal lines, reason as follows: m=0, therefore, for any x,,(x*0=0), y=b
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\n" ); document.write( "Vertical lines,are not as reasonable. Books say to stay away from y=mx +b for vertical lines. Lets do it this way. For any y, x=#. This is the only form that allows y to vary, and x remain constant,( like 0*y = x+b,,,,but mathematically not)
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\n" ); document.write( "If a VERTICAL line is coordinated, it is (y1,x),(y2,x) (y3,x),etc: hence x=#, for all y\"s
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\n" ); document.write( "If a HORIZONTAL line is coordinated, (y,x1),(y,x2), (y,x3), etc: hence y=# for all x\"s
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\n" ); document.write( "When it is all done, perhaps the best way to remember is that either y=# or x=#, and pick the one that works. \n" ); document.write( "

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