Answer with explanation:
Let us assume that the 2 functions are:
1) f(x)
2) g(x)
Now by definition of concave function we have the first derivative of the function should be strictly decreasing thus for the above 2 function we conclude that

Now the sum of the 2 functions is shown below

Diffrentiating both sides with respect to 'x' we get

Since each term in the right of the above equation is negative thus we conclude that their sum is also negative thus

Thus the sum of the 2 functions is also a concave function.
Part 2)
The product of the 2 functions is shown below

Diffrentiating both sides with respect to 'x' we get

Now we can see the sign of the terms on the right hand side depend on the signs of the function's themselves hence we remain inconclusive about the sign of the product as a whole. Thus the product can be concave or convex.
Answer:
18
Step-by-step explanation:
For this case we have that by definition, the equation of the line in the slope-intersection form is given by:

Where:
m: It is the slope of the line
b: It is the cut-off point with the y axis
We have the following points through which the line passes:

We find the slope of the line:

Thus, the equation of the line is of the form:

We substitute one of the points and find b:

Finally, the equation is:

Answer:

Two 2 1/3 + 2 1/3 = 4 2/3
8/1 - 4 2/3 =
14/3 - 8/1 = 6/2
Point-slope form: y-y1 = m(x-x1)
Standard form: ax + by = c
Slope-intercept form: y = mx+b
Start by finding the slope. We know it is negative since the line is decreasing. The slope is -4/3.
To create point-slope form, we need to get one point from the graph. Let's use (3,0).

To create slope-intercept form, we need the slope and the y-intercept. The y-intercept is the point where our equation crosses the y-axis. For this equation, it is 4.

To get standard form, solve the equation in terms of C.
Point-slope form: y = -4/3(x-3)
Slope-intercept form: y = -4/3x + 4
Standard form: 4/3x + y = 4