Posted by Unknown on Tuesday, September 3, 2013 at 10:44pm.
1. Why do you think that the slope of a vertical line is called "undefined?"
2. Can you find the equation of a line if you are given the slope and the x-intercept? If so, explain how. If not, explain why you can't.
Geometry - Reiny, Wednesday, September 4, 2013 at 12:27am
Consider any two points that form a vertical line,
e.g. (x, a) and (x, b)
slope = (b-a)/(x-x)
= (b-a)/0 , but division by zero is "undefined"
Thus the slope of a vertical line is undefined.
2. Yes, given the slope m and the x-intercept we can find the equation of the line
e.g. slope = 4 , x-intercept is (3,0)
y = 4x + b
but (3,0) lies on it, so
0 = 4(3) + b
b = -12
y = 4x - 12
in general if the slope is m and the x-intercept is k
the equation is
y = m(x-k)
for the above, y = 4(x-3)
which expands to y = 4x - 12 , as above.
Answer This Question
More Related Questions
- algebra - Write the equation of the line with x-intercept (–8, 0) and undefined ...
- math - i have more than one question so if u no any of the answers please tell ...
- Math - Finding the slope and y-intercept for x = -9, I beleive is (-9, 0) and ...
- math/algebra1a - write the equation of the line with x-intercept (-7, 0) na d ...
- algebra - Find the slope and y-intercept. x=7 I know that the slope is undefined...
- Math(Please help) - Write an equation of the line satisfying the given condition...
- Math - Write an equation of the line satisfying the given condition. a) x ...
- Math /Algebra - I was challenged with this question: Explain why the formula for...
- Math - I am supposed to find the slope and y intercept of x=-9 Just waned to ...
- algebra - Write the equation of the line with x-intercept (–6, 0) and undefined ...