Meh : fill in the blanks
which functions have a positive rate of change and which have a negative rate of change?
column a column b
2x + 3y = −9 a. positive
b. negative
y = 3x − 6

x y
−1 9
0 7
1 5

x y
2 −8
3 −7
4 −6

Convert to slope-intercept form, y = mx + b.



Subtract 2x to both sides:



Divide 3 to both sides:



Now it's in slope intercept form, y = mx + b where 'm' is the slope. So the slope here is -2/3, which is Negative.



This is already in slope intercept form. So the slope here is 3, which is Positive.

For #3 and #4, take any two points from the table and plug them into the slope formula.



Let's take (0, 7) and (1, 5).
               x1 y1       x2 y2



Subtract:



Divide:



So the slope is negative.

For #4, let's take (2, -8) and (3, -7)
                         x1  y1       x2  y2



Subtract:



Divide:



So the slope is positive.