3 4 12 x y - = 3 4 12 0, ,0 x y - = 3 4 12 0, 3 ,0 x y - =

Graph a line in standard form (COVER-UP method)
1. Write equation in standard form Ax + By = C
3x - 4 y = 12
2. Start to write out coordinates for the x and y
intercepts, leaving space for their values
Graph a line in slope-intercept form
1. Write eqn. in slope-intercept form y = mx + b
Graph a line in point-slope form
1. Write eqn. in point-slope form y - y1 = m(x - x1)
2
y = - x -1
3
2. Identify slope (m) and y-intercept (b)
3
y + 2 = ( x - 1)
4
2. Identify the point (x1, y1) and the slope m
3x - 4 y = 12
( 0, )
( , 0)
3. Find y-intercept. Set x = 0 (cover up x term) and
solve for y. Record result.
3x - 4 y = 12
3
y + 2 = ( x - 1)
4
2
y = - x -1
3
m=-
y1= -2
2
b = -1
3
(1, - 2) POINT!
4. Find x-intercept. Set y = 0 (cover up y term) and
solve for x. Record result.
3
y + 2 = ( x - 1)
4
3x - 4 y = 12
5. Graph by plotting ONLY the x- and y-intercepts
and drawing a line through the two points.
note opposite sign
for both values
3. Plot and label the y-intercept (0,b)
( 0, --33)
( , 0)
( 0, - 3)
(44 , 0 )
x1= +1
rise
4. Use slope =
to plot a second point
run
m=
3
4
3. Plot (x1, y1)
4. Use slope =
rise
to plot second point
run
5. Draw a line through the two points.
5. Draw a line through the two points.
Special Lines (Be brilliant! Just know these lines!)
x = constant
x=0
y=x
a vertical line with undefined slope
a vertical line with undefined slope at x = 0 :
a line with a positive slope = 1,
that crosses the x–axis at x = constant
THE y-AXIS!
passes through (-2,-2),(-1,-1),(0,0),(1,1),(2,2) …
y = constant
y=0
y = -x
a horizontal line with zero slope
a horizontal line with zero slope at y = 0:
a line with negative slope = -1,
that crosses the y–axis at y = constant
THE x-AXIS!
passes through (-2,+2),(-1,+1),(0,0),(+1,-1),(+2,-2) …

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