Question

Which functions have a positive rate of change and which have a negative rate of change?
1. 2x – 3y = 9
2. y = −4x + 5
3.
x y
−1 −5
1 1
3 7
4.
x y
1 −2
2 −6
3 −10
A.
positive
B.
negative

Answer 1

Think about it this way: if, as x gets bigger, so does y, then that's a positive rate of change. If, as x gets bigger, y gets smaller, then that's a negative rate of change. "Rate of change" is also just a fancy way of saying slope, so if the slope of the line is positive, the rate of change is positive, etc.

Answer 2

Oh okay thanks for explaining :D

Answer 3

:)