document.write( "Question 326105: Write the equation for the following problem? a vertical line that passes through (4,-7) \n" ); document.write( "
Algebra.Com's Answer #233406 by solver91311(24713)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "Recall the slope formula: The difference in the -coordinates divided by the difference in the -coordinates.\r
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\n" ); document.write( "\n" ); document.write( "In order for the line to be vertical, -coordinates have to be equal. If the -coordinates are equal, the denominator (the difference in the -coordinates) has to be zero. If the denominator is zero, the slope is undefined. So a vertical line has an undefined slope and is a set of ordered pairs where all of the -coordinates are identical. If you want your vertical line to pass through the point , then all of the points on your line must have an -coordinate of 4, and you don't care what the -coordinate value is. The only way to describe such a set of ordered pairs is:\r
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\n" ); document.write( "\n" ); document.write( "Which, if you consider the possibility of writing it as:\r
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\n" ); document.write( "\n" ); document.write( "is, as you can see, written in Standard Form. The equation of a vertical line is the only equation of a line that CANNOT be written in slope-intercept, point-slope, or two-point form because all of these forms require expressing the slope.\r
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