Graphing the line....?

Question

Calculate the line tha tpasses through points (7,-1) and (3, - 2) find the
a. slope
b. y intercept

Can someone help me here....and how would I graph this??

Answer 1

The coordinates for the points are given in (x,y) order. You just plot the two points and draw a line passing through both of them and extending out both directions.

A. Slope is Rise/Run or (Change in Y)/(Change in X)
or sometimes written as (Y2-Y1)/(X2-X1)
so you subtract one of the Y's from the other and in the same order subtract one of the X's from the other...

Y2 - Y1
(-1) - (-2) = -1 + 2 = 1 (using the first point as (X2, Y2))
(-2) - (-1) = -2 + 1 = -1(using the first point as (X1, Y1))
X2 - X1
7 - 3 = 4 (using the first point as (X2, Y2))
3 - 7 = -4 (using the first point as (X1, Y1)0
(Y2 - Y1) / (X2 - X1)
1 / 4 (slope using the first point as (X2, Y2))
-1/-4 = 1/4 (slope using the first point as (X1, Y1))
notice that the slope came out the same with either calculation.. a positive slope means that the line goes up as it goes from left to right.. and it goes up 1 for every 4 that it goes across.

y = mx + b is the slope intercept form of an equation where x is the independent variable (on the horizontal axis), y is the dependent variable (on the virtical axis), m is the slope and b is the value of y when x = 0 (y-intercept)

plug in known values for one of the points
y = (1/4)x + b (slope = 1/4 but we don't know b yet.. so solve for it...

-1 = (1/4)7 + b (put in values of x and y from first point)
-1 = 7/4 + b
-1 - (7/4) = b
-(4/4) - (7/4) = b
-(11/4) = b

a. slope = 1/4
b. y-intercept = -11/4
c. slope intercept equation: y = (1/4)x - 11/4


*** sorry Hellokitty.. your link does not work

Answer 2

hmm, this is fairly basic stuff. If you can't put a straight line through two plotted points, you're in real trouble. I would suggest that you talk to your teacher. Sure, we can give you the answer, but it sounds like you need to understand the concepts involved, like how to draw graphs and know what the terms 'slope' and 'y-intercept' mean.

Answer 3

use the slope formula... to derive the slope.
Y2-Y1/X2-X1

and then apply the slope intercept equation.
y-Y1=M(X-X1)

Answer 4

http://answers.yahoo.com/question/index;...


I need math help too! I need help on number 2! Please click the link above please!