SOLUTION: I do not understand how to find the standard equation of a line through the given point A (2,1) that satisfies the given condition(perpendicular to the y-axis)

Algebra ->  Equations -> SOLUTION: I do not understand how to find the standard equation of a line through the given point A (2,1) that satisfies the given condition(perpendicular to the y-axis)      Log On


   

Question 960511: I do not understand how to find the standard equation of a line through the given point A (2,1) that satisfies the given condition(perpendicular to the y-axis)
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Standard form as a generalized model can be ax%2Bby=c.

If you solve for y in terms of x, you find slope is -a%2Fb. "Perpendicular to the y axis", means slope is 0. Using the formula taken from standard form, this means -a%2Fb=0. This means, highlight_green%28a=0%29.

You have so far, by=c.

You want the line to contain the point A (2,1). The coordinate of x is no longer important; all possible values of x will be on the horizontal line (given now that slope is 0). y is 1 everywhere on this line.

b%2A1=c, but also y=c%2Fb to give the slope-intercept form of the equation. Obviously this is only a constant, and therefore c/b is the y-intercept. You know that the line is highlight%28y=1%29.

If you really want as "STANDARD FORM", then adjustment is not needed. b=1, and c=1.
highlight%280%2Ax%2B1%2Ay=1%29, but this is more formal than necessary.