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
Answer:
m∠7 = 63 degrees
m∠8 = 117 degrees
m∠9 = 63 degrees
Step-by-step explanation:
When two lines intersect at a point, then they formed 2 pairs of vertically opposite angles and 4 pairs of linear angles
- The vertically opposite angles are equal in measures
- The linear angles have a sum of 180°
In the given figure
∵ There are two lines intersected at a point
∴ The angle of measure 117° and ∠8 are vertically opposite angles
∴ ∠7 and ∠9 are vertically opposite angles
∴ The angle of measure 117° and ∠7 are linear angles
∵ The vertically opposite angles are equal in measures
∴ The angle of measure 117° and ∠8 are equal in measures
∴ m∠8 = 117°
∵ The sum of the measures of the linear angles is 180°
∴ m∠7 + 117° = 180°
→ Subtract 118 from both sides
∵ m∠7 + 117 - 117 = 180 - 117
∴ m∠7 = 63°
∵ m∠7 = m∠9 ⇒ proved up
∴ m∠9 = 63°
y=4/3-x/6
Step-by-step explanation:
6y/6+x/6=8/6
y+x/6=4/3
-x/6 -x/6
y=4/3-x/6
