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##### Videos w/ Notes  # Y

Ex: Graph X + 2y = 4

Step 1: Set Y = 0 and solve for X

x=2 (0)=4

x=2(0) =4

x=4

Step 2: Set X=0 and solve for Y

0 + 2y = 4

0 + 2y = 4

2      2

y=2

Step: 3: Put a point on X-axis at x = 4 and a point on Y-axis at y=2

# = 4.9

## STOP!

Convert ( 3.2, 6.6 ) +  +/- notation

Step 1: Find the middle of the interval by adding the endpoint and dividing by 2

6.6 + 3.2

2

Step 2: Find the distance from the middle to the endpoint

6.6 - 4.9 = 1.7

Step 3: In +/- notation

4.9 +/- 1.7

## Plotting Points

Ex. Plot (2,3) = (x,y)

X tells you how far to go right or left

Y tells you how far to go up or down

So, for (2,3), start from the origin.  I'm going:

2 units right because x=2

3 units up because y=3

Ex: Plot ( -1, -4)

This time, Because X = -1 I'm moving 1 unit left

and because Y = -4, I'm moving 4 units down

# (-1,-4)

## Graph Through Origin and Slope

Ex: Graph Y = 3x

Step 1: Set X=0, Solve for Y

Y=3(0)

Y=0

(0,0)

Step 2: Set X=1, Solve for Y

Y=3(1)

Y=3

(1,3)

Step 3: Plot the points. Join with a line.

Ex: Y=1x or X

# Y

## Calculate Slope

Ex: Find slop of the line joining (3,-1) and (5,6)

b= y2 - y1

x2 - x1

Step 1: Identify the given points, as (X1,Y1) and (X2 Y2)

(31 - 1   (5,6)

X1    Y    X2  Y2

Step 2: Write slop formula, plugging in the values

b= y2 - y1

x2 - x1

# 3.5 or 7/2

6 - (-1)

5  -  3

Use calculator: Shown in video

6 - (-1)

5  -  3

Step 1: Set X=0, Solve for Y

Y=1/4 (0)

Y=0

(0,0)

Step 2: Set X=4 (the denominator of the fraction)

Y=1/4 (4)

Y=1/4 (4)

Y=1

(4,1)

Step 3: Plot the point. Draw the line.

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