Solve and graph on a number line
12 < 5 ­ 2x
4 < 3x + 1 ≤ 13
Find the slope and y­intercept.
12x + 4y = 8
5x ­ 3y = 6
What is the equation of the line?
A. slope = 2 ; y­intercept (0 , ­3)
B. rate of change = ­½ ; y­intercept (0 , 6)
C. m = ­6 ; b = 7
D. slope = ¾ ; y­intercept (0 , 0)
E. slope = 0 ; y­intercept (0 , ­ 5)
Write the equation of the graph shown below.
Write the equation of the graph shown below.
But, how can we find the equation of a line if the point we know isn't the y­intercept?
For example: We have the point (6, ­3) on a line whose slope is ­2. What is the equation of the line?
y
= starting
value
+ RATE x
­
or
OF
CHANGE
Now try:
A. (2 , ­3) , m = ½
y = mx + b
B. (­1 , ­2) ; m = 4
So, we have looked at writing equations of lines from graphs, and given a slope and a point on the line... but what happens when we only know two points on the line?
Example:
(1 , 6) ; (3 , ­4)
Writing equations in slope­intercept form, that goes through the following points.
A. (3 , 9) (1 , 5)
B. (­2 , 7) (1 , 1)
C. (­1 , 3) (­4, ­3)
D. (4 , ­5) (1, ­5)