Answer:
l think that the answer is (-3,2). pliz can you mark me the brainest.
Use the linear slope formula to solve for m:
m=(y2-y1)/(x2-x1)
using the points (-1,1) and (1,5) you can find the slope for the first interval:
m=(5-1)/(1-(-1))
m=4/2
m=2
you can double check by using the same formula on the second interval, which is (1,5) to (3,9).
m=(9-5)/(3-1)
m=4/2
m=2
therefore, the rate of change is 2.
Answer:
(a)Therefore the value of x=
(b) Therefore the value of x 
Step-by-step explanation:
Horizontal tangent line: The first order derivative of a function gives the slope of the tangent of the function. The slope of horizontal line is zero.If the slope of tangent line is zero then the tangent line is called horizontal tangent line.
(a)
Given function is,

Differential with respect to x

For horizontal tangent line, f'(x)=0
3+ 3 cos x= 0
⇒3 cos x=-3
⇒cos x=-1
⇒x = 180° 
Therefore the value of x=
(b)
Given that, the slope is 3.
Then,f'(x)=3
3+ 3 cos x= 3
⇒3 cos x= 3-3
⇒cos x=0
⇒x = 90° 
Therefore the value of x 
I’m pretty sure the answer is C.
Yes those are right. all the steps and answers are correct.