UNIT 7 - OBJECTIVE 4 - THE STRAIGHT LINE
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There are several formulas for the equation of a line
1) Point slope of a line

Use this when given slope m and a point on the line.
Use this when given two points on a line by finding m first.

2) Slope intercept from a line (y-intercept)
y=mx+b

Use this when given slope m and y-intercept

3) General form of a line
Ax+By+C=0 					The graph is always a line.

4) Special lines

Equation : y=b

Equation: x=a

EXAMPLE 1
Find the slope of the line whose equation is 3x+2y=6

Solve the equation for y=mx+b because m is the slope.

EXAMPLE 2
Write the equation of the line through (-2,4) and (-9,2).
Find the slope

Use the point slope form of a line (you can use either point)

You can use fraction or avoid fraction.
OR

EXAMPLE 3
Find the equation of line through (1,-2) and perpendicular to 3x+2y=6

Find the slope of the given line by solving for y
2y=-3x+6
y=-3/2x+3			slope=-3/2

The slope of the perpendicular to the given line has a slope equal to -(1/(-3/2)) = 2/3
Now we use point slope formula