Posted by **Carmin** on Wednesday, June 24, 2009 at 9:48am.

Which of the following is TRUE about the line through the points (–1, 4) and (–1, 2)?

Please EXPLAIN/SHOW WORK.

A. The slope is undefined

B. The slope is negative

C. The slope is 0

D. The slope is positive

- Math -
**Carmin**, Wednesday, June 24, 2009 at 9:49am
A. The slope is undefined.

B. The slope is negative.

C. The slope is 0.

D. The slope is positive.

- Math -
**MathMate**, Wednesday, June 24, 2009 at 10:35am
The slope m between two points P1(x1,y1) and P2(x2,y2) can be calculated using

m=(y2-y1)/(x2-x1) where x2≠x1

if x2=x1, and y2≠y1, it means that the line is vertical (slope is infinite or undefined)

if x2=x1 and y2=y1, the two points are coincident and the line is indefinite.

In all other cases, the slope m can be obtained by the formula above.

For the case in question,

P1(–1, 4) and P2(–1, 2)

so x2=x1=-1, and y2≠y1

Therefore the line is vertical.

Post again if you need more explanations to choose the answer.

- Math -
**Carmin**, Wednesday, June 24, 2009 at 11:40am
If the line is vertical there is no slope making it undefined correct?

- Math -
**MathMate**, Wednesday, June 24, 2009 at 6:35pm
correct!

- Math -
**MathMate**, Wednesday, June 24, 2009 at 6:36pm
Sorry, it should read:

If the line is vertical **the slope is infinite** making it undefined.

## Answer This Question

## Related Questions

- slope - Find the slope of the line passing through the given points using the ...
- Algebra1 - Complete this sentence with the correct choice: y = 4 is a horizontal...
- Algebra - Doing a slope project in Algebra. The instructions are to make a ...
- math/algebra - find the slope of any line perpendicular to the line through ...
- Algebra 1 help - Can someone tell me if my answers are right and explain how you...
- Algebra - Find the slope of any line perpendicular to the line through the ...
- math - 1. What is the slope of the line that passes through the points (-2, 5) ...
- algebra - Could someone please check my work. what is the slope of the line that...
- Math /Algebra - I was challenged with this question: Explain why the formula for...
- Math...Please help I need this done by 6:00 - This was the question: Explain why...

More Related Questions