how can i find the slope for these problems?

Question

m= y2-y1/ x2-x1 is the formula

(4,5) & (-1,2) so, wouldn it be:
2-5 = -3 =3
------ -- --
-1-4 -5 5

also y=2x don't you just divide y out of the equation?

y=2x
-- --- = 2? since y = 2x, then 1/2y =x
y y

finally 11=5x-9y
i'm lost on this one.

Answer 1

1) You have the first one right.

2) In the case of y = 2x, the slope is 2. Example. The points are (2,3) and (4, 7). According to the slope equation:

(7-3) / (4-2) = 4 / 2 = 2.

3) To solve this problem, first bring y to it's own side, as shown:

11 = 5x - 9y

a. Subtract 5x from both sides.
-5x + 11 = -9y

b. Divide -9 from both sides.
(-5/-9)x + (11/-9) = y

c. 5/9 is your slope because it's next to the x variable. Input two coordinates that fit the equation and check the work. Here's a better view of the finished equation:

y = (5/9)x + (11/9)

I hope this helps; God Bless!

Answer 2

Well, firstly, negative 3 is not equal to 3.

In the first case, you have (4,5) & (-1,2)
x1 = 4, x2 = -1, y1 = 5, y2 = 2.

m = (y2 - y1)/(x2-x1)

m = (2-5)/(-1-2)

That gives you
-3/-3
which is equal to
1

The first slope is 1.

In the case of y=2x, this actually follows the format y=mx+b.

You can also think of it as

y = 2x + 0.

The y-intercept is zero, the slope is 2.

the last one:
11=5x-9y

First, isolate y.

11-5x = -9y
divide both sides by -9

y = (11/-9) - (5x/-9)

Simplify, by moving negative signs from denominator to numerator.

y = -11/9 -(-5x/9)

Taking something minus negative equals positive.

y = -11/9 + 5x/9

y = (5/9)x - 11/9

So the slope is 5/9.

Answer 3

For (4,5) & (-1,2) I prefer
(5 - 2) / (4 - (-1)) = 3/5
which agrees with your result.

for y=2x
the slope is simply 2

11 = 5x - 9y
9y = 5x - 11
y = (5/9)x - 11/9
The slope is 5/9