Question

which table shows a constant rate of change of -3?
http://gyazo.com/13849bc2dda69f87364a08e1705380d9

Answer 1

?

Answer 2

They want you to find the table that shows you have a slope of -3 no matter what points you choose from it

Answer 3

For example, the first table has points (3,-8) and (4,-5).
Do you know how to find the slope of a line going through these two points?

Answer 4

no.

Answer 5

Do you know the slope formula is (change of y)/(change of x)
?

That is,
\[\text{ slope } =\frac{y_1-y_2}{x_1-x_2}\]

Answer 6

Do you know how to use that formula?

Answer 7

i dont.

Answer 8

Well lets look at the points I have (3,-8) and (4,-5)
the second number represents a y-value
the first number represents a x-value
and together they correspond to each other in that pair
(x,y)

So anyways we can let \[(x_1,y_1)=(3,-8) \text{ and } (x_2,y_2)=(4,-5) \]
Then plug into the formula above and simplify.
replace x_1 with 3
replace y_1 with -8
replace x_2 with 4
replace y_2 with -5

Answer 9

what does the y over the 2 mean? and the x?

Answer 10

what does the 2 over the y and x mean *

Answer 11

You mean x_1
That is x subscript 1

Answer 12

\[\text{ replace } x_1 \text{ with } 3 \]
\[\text{ replace } y_1 \text{ with } -8\]
\[\text{ replace } x_2 \text{ with } 4 \]
\[\text{ replace } y_2 \text{ with } -5\]

Answer 13

its the fourth one.

Answer 14

what do you mean? the fourth one?

Answer 15

i will write it without latex
we need to use this formula
(y1-y2)/(x1-x2)

where (x1,y1) is (3,-8)
and
where (x2,y2) is (4,-5)

Answer 16

So let's do the top of the fraction...
y1-y2
what is -8-(-5)?

Answer 17

http://gyazo.com/5e8d6bb8cdd0d7772501bddb943b09f2

Answer 18

i jut guessed since i dont understand anyway.. but thanks.