Question

still need some help with point slope formula...

Answer 1

????

Answer 2

i don't understand how to equate the formula. so if i have (2,3) and (4,5) as points, I can find the slope, but then finding the y intercept by using the point slope is what confuses me Is there another way to find the y intercept?

Answer 3

point-slope form is just one way to write the equation of a line if you know that line goes through a specific point and its slope. the form looks like this: y - y1 = m(x - x1)

slope-intercept, which is what you're probably referring to is just a specific case of point-slope form. It's just another way to write the equation of a line. Having it written in this form makes it easy to identify the y-intercept. the form looks like this: y = mx + b.

there are many other ways to write the equation of a line, and each has its merits....

Answer 4

Try this:
y-y1 y2 -y1
---- = ------
x-x1 x2 - x1

y2 -y1
Actually, ------ is the slope, which is m :S
x2 - x1

Answer 5

i can get the slope, but how do i get the y intercept, with the 2 points?

Answer 6

do you want an example?

Answer 7

wait... why do you need the y-intercept? is it for graphing?

Answer 8

y-y1 y2 -y1
---- = ------
x-x1 x2 - x1

y-y1 = m(x-x1)
y = mx -mx1 +y1
y = mx +(-mx1 +y1)

(-mx1 +y1) is the y-int :D

Answer 9

because, if you already have the equation of a line, all you really need to do is set x=0 and solve for y... no matter what the equation of the line is in....

Answer 10

i guess i need to find the slope and then put it in slope intercept form

Answer 11

so you already have an equation?

Answer 12

-3=-2/3(2)+b

Answer 13

-2/3 being the slope.

Answer 14

I assume (2, -3) is the point you know the line goes through?

Answer 15

yes, that is one point.. the other is (-4,1)

Answer 16

then there's nothing wrong with -3=-2/3(2)+b.
Is solving this equation a problem?

Answer 17

seems to be, since i am not getting the correct y intercept. i am getting -1.67

Answer 18

b = -5/3...

Answer 19

is that it?

Answer 20

yes, i cannot seem to get that answer.

Answer 21

-5/3 = -1.66667 (approx)

Answer 22

i seem to be challenged with the signs

Answer 23

what signs?

Answer 24

ok, never mind. i did get the correct answer, just not in fraction form. i wish i had my old scientific calculator that gave answers in fractional form! thanks for your help:)

Answer 25

np... way to stick with it... little bit of advice... get to know fractions... do not avoid them....