HELP, please i have a test tomorrow - - Options

[tofumonzter]

so mr/mrs math please help me on this. i have a test tomorrow. and if you can help me figure this out i'll be your slave for one day or anything. pleaseeee~

ok this is what i need to know.

i need to know how to

convert y=mx+b into (y2-y1)=m(x2-x1) and then (ax+by)=c
basicly it's slope-intercept form into point-slope form and then standard form

PROBLEM : slope 2; y-intercept 5

please all the smart people that knows good math help me on this, and i'll be your slave for one day

PLEASE

[Spirited Away]

I think this website or this cheat sheet might help.


Just look around online. There are a lot of examples that may help you study.

[whomps]

I just reread this right now and find out that it's REALLY confusing. But it took me awhile to type it so blah. Meh. What are you taking right now?

Y = mx + b
Y is the Y, m is the slope, x is x, and be is the y intercept.

If they give you the equation Y = mx + b, they give you the slope and the y-intercept. You can already find another point on the line by using the the y-intercept and slope.

The y-intercept already gives you a point..>> (0, y)

(y2 - y1) = M
(x2 - x1)

^ To find another point.

So when you have y2-y1 = m(x2-x1), you substitute in your two points.
A point would be (x1, y1) and (x2, y2)

Okay so you found the two points, LETS PRETEND they're uhm (4, 1) and (6,3).
to get them into (ax+by=c) form, you have to substitute them.
Soo substituing them, you would receive two equations because there are two points.

First equation >> 4a+ 1b = c ---- Now you have a system of equations! =o
Second equation >6a + 3b = c

To solve the system of equations, multiply the first equation by (-3)

-12a + -3b = -3c
6a + 3b = c

Now add them. Straight down. To get one equation..

-6a = -2c << Divide (-2) by both sides
To get..
3a = c

Now, go back to the FIRST equation.

4a + 1b = c

Substitute C

4a + 1b = 3a

Solve the equation. Substract 3a from both sides,

a + b = 0

Change ^ that to (b = -a)

Uhm.. and your original equation

ax + by = c

Substitute. B and C

ax + (-a)y = 3a

Divide all sides by A.

x + (-y) = 3

There's an easier way to do it I think.. because m = -a/b but uhm yeah.
Got the last part (ax + by = c) from this one page..

[tofumonzter]

thanks eve and loan, you two are such a awesome poop to me.