Question

What is the slope of the coordinates (1,3) and (2,-1)

Answer 1

do you know the slope formula?

Answer 2

m=y1-y2/x2-x1

Answer 3

(x,y)

Answer 4

good so far?

Answer 5

ya but i dont get how to plug it in

Answer 6

your (x,y) are your numbers so just assign x1 and y1 to first bracket and x2 and y2 to second

Answer 7

(x1,y1)= (1,3)
(x2,y2)=?

Answer 8

so is it 3-(-1)/1-2 ?

Answer 9

So if thats the slope then what would be the equation?

Answer 10

first lets finish the slope the numerator would be 4
what would the denominator be?

Answer 11

-1

Answer 12

right so the slope or m = 4/-1 or -4

Answer 13

ya i got that but what do i do to get the equation because i already have the slope

Answer 14

In order to make a linear equation y = mx + b, you need a slope and a y intercept.
We have a slope now, but need a y intercept.
Pick one of the points, it doesnt matter which one.

Answer 15

then put the x and the y value into y = (-4)x + b
Then solve for b

Answer 16

Which point do you want to use...like I said it doesnt matter which one.

Answer 17

(1,3)

Answer 18

(x, y )
(1, 3) now substitute the x and the y into y = (-4)x + b

Answer 19

b = -1?

Answer 20

y = (-4)x + b
3 = (-4)(1) + b
3 = -4 + b
+4 +4
7 = b
what did you do wrong?

Answer 21

when i moved the 4

Answer 22

i forgot it cancels that four out so i got it mixed

Answer 23

right, always make sure you are doing the opposite

so now we know m = -4
b = 7

all you have to do is put them into y = mx + b
y = -4x + 7

do you see?

Answer 24

yes

Answer 25

when you are finding an equation this way and you have two points, pick the one with what look like the easiest numbers, in this case both points were similar.

Have a good one!

Answer 26

thanks