m = (y2-y1)/(x2-x1)
m = (6-4)/(4-0)
m = 2/4
y = mx + c
6 = (2/4)(4) + c
c = 4
Thus, the equation is y = (2/4)x +4
The maximum number of turning points in a cubic function is 2.
In this case,

The discriminant is

, which means the derivative has no real roots. This means there are no critical points and thus no turning points/relative extrema.
4/7 the question is relative
B it is going to give you the answer
Option C: 90° is the value of x.
Explanation:
The given expression is
for 
We need to solve the expression.
Thus, we have,

Subtracting both sides by 4, we have,

Adding both sides by 8 sin x, we get,

Dividing both sides by 10, we have,

Taking
on both sides of the equation, we get,


Thus, the value of x is 90°
Hence, Option C is the correct answer.