Vocabulary
What do we call rise over run?
What is slope?
(0,1), (2,7)
What is 3?
Passes through (1,9), slope = 2 (point-slope form)
y - 9 = 2(x - 1)
y = -5x + 2
m = -5
b = 2
Slope equation
y2 - y1
______
x2-x1
Lines with a slope of 0 are ___________ and lines with an undefined slope are _____________.
horizontal (0); vertical (undefined)
(1,2), (4, 7)
What is 5/3?
Passes through (-4,-5), slope = 3/4 (slope-intercept form)
y = 3/4x - 2
3x + y = -4
m = -3
b = -4
Slope intercept form equation
y= mx + b
The horizontal change.
What is Run?
(-2,3), (7, -4)
What is -7/9?
Passes through (3,-6) and (-1,2) (point-slope form)
y + 6 = -2(x - 3)
Graph the line y = 3x - 2
y-intercept = -2, slope of 3 (rise = 3, run = 1)
standard form equation
Ax +By = C
The y-coordinate of the point where a line crosses the y-axis.
What is the y-intercept?
Is (5, -3) a solution to 2x + y = 13?
No (Plug in the x and y-values and you get 7 = 13)
Passes through (4,-4) and (8,-10) (slope-intercept form)
y = -3/2x + 2
2y - 2x = 8
m = 1
b = 4
Point slope form equation
y - y1 = m(x-x1)
Parallel lines have the _______ slope; perpendicular lines have slopes that are ____________ and ___________.
same (parallel); opposites and reciprocals (perp.)
Find k so that (-1, 4) is a solution to y = 3x - k
k = -7
-3y = 3x + 4
m = -1
b = -4/3