How to find the slope of the tangent line at a point on a curve?

In a graph with several intervals o data how does a constant interval appear? what type of scenario produces a constant interval?

Ineed no it anyone can see this

26) -2(7x) = (-2 • 7) x a. associative property of addition b. associative property of multiplication c. commutative property of multiplication d. commutative property of addition