document.write( "Question 21959: My line is (-7, 2) ; (-7, -2). Obviously this is a horizontal line. Also, this does not have a y-intercept. How would I find the equation of this line? In the formula y = mx+b, would \"b\" represent the x-intercept in this case? Thank you in advance! \n" ); document.write( "

Algebra.Com's Answer #10607 by Earlsdon(6294) $\"\"$ $\"About$

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If your line is (-7, 2) ; (-7, -2) then the line is a vertical line (straight up-and-down) rather than a horizontal line (flat, side-to-side).\r
\n" ); document.write( "\n" ); document.write( "The equation of this line would be: x = -7 and, you are right, there is no y-intercept, only an x-intercept (x = -7), so the slope-intercept form has no meaning for such a line. Since the y-coordinate of this line can take on any value you please, the coordinate of any point on this line can be written: (-7, a), where a is any real number.
\n" ); document.write( "A vertical line has an undefined slope (m) and no y-intercept (b) so it cannot be represented by the slope-intercept form of the equation.\r
\n" ); document.write( "\n" ); document.write( "Also, the equation: y = x represents a line that is at 45 degrees to the axes and passes through the origin.\r
\n" ); document.write( "\n" ); document.write( "Here's the graph of y=x:
\n" ); document.write( " $\"graph%28300%2C200%2C-10%2C10%2C-10%2C10%2Cx%29\"$ \n" ); document.write( "

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