Find the slope of the line.......Algebra Help PLeaseee!??

Question

Multiple Choice, need help please...i just cant get it. Anything that has a / through it means it is a fraction.

(12, -3) and (1, -1)

A. -11/2
B. 2/11
C. 11/2
D. -2/11


(0, 1/3) and (1/2, 2/3)

A. 2/3
B. -3/2
C. 3/2
D. -2/3

Answer 1

Slope is rise/run, so for a line going through two points (x1, y1) and (x2, y2), it's (y2 - y1) / (x2 - x1).

For the first question, it's (-1 - -3) / (1 - 12) = (2 / -11) = -2/11, or answer D.

For the second question, it's (2/3 - 1/3) / (1/2 - 0) = (1/3) / (1/2) = 2/3, or answer A.

Answer 2

Do you know the formula for slope?
Delta Y
----------
Delta X

That's the same as (y2-y1) / (x2-x1)

For the first question...
(12,-3) and (1,-1)
12 is X1 and 1 is X2 (or you can put it the other way around... but you MUST put Y1 and Y2 in the SAME ORDER you put the Xs in)
If you follow my way, though, then Y1 would be -3 and Y2 would be -1
Then using the formula...
(-1 -(-3)) / (1 - 12)
That is the same thing as (-1 + 3) / (-11)...
Therefore, the answer is 2 / -11... which is the same thing as -2/11 (Choice D)

The second question applies the same logic
Let's say X2 and X1 are 1/2 and 0 respectively (meaning in that order)... and Y2 and Y1 are 2/3 and 1/3 respectively.
Therefore...
Let's use that formula again (y2-y1) / (x2-x1)
That would be:
(2/3 - 1/3) / (1/2 - 0)
2/3 minus 1/3 is 1/3
And 1/2 - 0 is... 1/2!
Now our final answer is (1/3) / (1/2)

... ewwwwwwwwwwwwwwwwwww!! Fraction over Fraction! This looks ugly! How to make this simpler?
Remember kids... it's illegal to divide fraction!
We must take the fraction in the numerator and MULTIPLY by the RECIPROCAL of the denominator ^_^

So it's (1/3) times (2/1)...
2/1 is the same thing as 2
So... (1/3) * 2 = 2/3
So the answer is A) 2/3

Hope it helps...

Answer 3

Every line between 2 points has 2 slopes! (Whoa)...Read further.
The magnitude of both slopes is the same but the sign is different.
For example, when u r climbing uphill, the slope is positive, when you are going downhill, the slope is negative. Thus the magnitude is same. Ok so far?

A slope of a line is calculated by a simple formula. You take 2 points say A and B. You use the formula the other guy here mentioned.
(y of B - y of A)/(x of B - x of A). That is your slope.

But how do you find what is A and what is B?

So before you find slope, you plot the points on a graph. Its easy, right?
A general convention, most people like to follow, is to use the right most point as B and the left most point as A.

In the examples you mentioned in ur question, (12,-3) and (0,1/3) happens to be left most points on the graph, So they are As.
The other 2 are obviously Bs.

Now do the math and find the slopes.
The answers are -2/11 (downhill) and 2/3 (uphill).

I hope this answers your question. Hope it will also help you in your tests.

Answer 4

To find the slope given two points subtract the y's over subtracting the x's. m = (y - y)/(x - x)
(12, -3) and (1, -1) : m = (-3 - (-1))/ (12 - 1) = -2/11 choice D

(0, 1/3) and (1/2, 2/3): m = (1/3-2/3) / (0 - 1/2) = (-1/3) / (-1/2)
Now you are dividing two fractions, which you do by multiplying by the reciprocal. (-1/3 )x (-2/1) = 2/3 choice A

Answer 5

(12, -3) and (1, -1)
slope = (-1 -(-3))/(1-12) = 2/-11 = -2/11

(0, 1/3) and (1/2, 2/3)
slope = (2/3 -1/3)/(1/2-0) = (1/3)/(1/2) = 2/3

Answer 6

(-1+3)/(1-12)=-2/11,
(2/3-1/3)/(1/2-0)=2/3

Answer 7

D, A

Answer 8

a.d