S LOPE I NTERCEPT FORM Y=Mx+b

"m" is the slope and "b" gives the y-intercept. Once the slope is given it is fairly easy to find which y equals. X and Y are any coordinate point on the line. If a slope is negative the line will go down

If a slope is positive the line will: Go up

T UTORIAL VIDEO m_Gg&feature=related

E XAMPLES Will the line go up or down? What is the y intercept? What is the slope? 1.Y=3x+1 2. Y=6x+3 3.Y=-7x+3

S OLVING FOR M, X, OR B When giving the slope and a coordinate, you plug it into the equation. For example slope of 2,giving the coordinate (4,2) X and y are given. 2=2(4)+b 2=8+b 2-8=b -6=b Y=2x-6

To find x (x,4) Slope 2 y-intercept=2 Y=Mx+b 4=2x+2 4-2=2x 2=2x 1=x Wenther you’re trying to find slope, y-intercept,x or y the process is always the same all you do is plug in.

E XAMPLES 1.Y-intercept= 1 (1,4)Solve for M or slope 2. Slope= 2 Coordinate =(1,5) Solve of b 3.Slope=-2 Coordinate = (x,1) Y-intercept = 3 Solve for x Leave in slope intercept form!

A NSWERS 1.Slope=3 Y=3x+1 2. y-intercept =3 Y=2x+3 3. x=1 Y=-2x+3

POINT- SLOPE FORM Another simple way of solving!

At this point, you should NOT be intimidated by the different strategies' used so far. Point-Slope Form is just another simple way of finding a straight line. So sit back, relax, and learn some math! P.S. To become interested in this subject, ask yourself: “What are other ways that I can utilize in order to find the equation of a straight line?”

POINT SLOPE FORMULA: y – y 1 = m ( x – x 1 ) The subscripts on the x and y represent a distinct point, (x,y), like (-1,-6). The other set of points would be the (x,y) WITHOUT the subscripts. M represents the given slope. There is no reason to be afraid of simple markings that help you clarify the problem.

Examples of a Point- Slope Formula Problem: Find the equation of the straight line that has slope m = 4 and passes through the point (–1, –6). Note: Its easier to identify using a Point-Slope Equation as long as there is a given slope and a given set of coordinates. DEFINE VARIABLES (PLUG THESE INTO YOUR EQUATION) m = 4 x 1 = –1 y 1 = –6 Note: The goal is to find the other set of coordinates WITHOUT SUBSCRIPTS. So your equation will look like this so far: y – y 1 = m ( x – x 1 )  Original Equation y – (–6) = (4)( x – (–1))  Post Plugging in

Lets finish this example! y – y 1 = m ( x – x 1 ) y – (–6) = (4)( x – (–1)) y + 6 = 4( x + 1) y + 6 = 4 x + 4 y = 4 x + 4 – 6 y = 4 x – 2 *So you can also write your equation in slope-intercept form as y = 4x-2

Use this video to help you further your understanding visually, in doing equations. watch?v=aQhb84bZDzw

Ok, so what if you were faced with a problem that gave you a graph, and asked you to use the point- slope formula to solve it? Well, all you have to do is use some investigative skills! So you know that you MUST have a slope and a set of points in order to use to point-slope formula. -Slope is rise/run, and in the graph, the rise/run= 2/3. Our slope is 2/3. -Pick a point, or a set of coordinates. Lets, say (5,2).

See? That wasn’t so hard! So what we have of our problem so far: Slope = 2/3 One Point = (5,2) We have everything we need to make an equation out of point-slope form. So lets plug it in, y – y 1 = m ( x – x 1 ) y – (2) = (2/3)( x – (5)) y - 2 = (2/3)( x - 5) y - 2 =(2/3)x-10/3 y = (2/3)x y = (2/3)x -1.34

Awesome! You just did Point – Slope Form in 2 Different ways! There are other resources on the internet if you need any extra help, but this formula is really simple and doesn’t need too much brainpower or thought. Good luck in all of your math studies!