Question

If f(x) is a linear function, what is the value of n?

Answer 1

The generic equation for a linear function can be expressed in the slope intercept form f(x) = mx + b, where m is the slope and b is the y intercept. For this problem we can first find the equation of the line. Then we substitute x = 7 to get the f(x) value, which is n at the point x = 7.

To find the equation of the linear function we first find the slope. Slope is defined as the change in f(x) divided by the change in x. As we are given a linear function, the slope at every point is the same. We can pick any two points known to find the slope.

Let's pick (3, 7) and (9, 16). The slope m is m = (16-7)/(9-3) = 9/6 = 3/2.

Now that we have the slope, we can plug in the slope and one of the points to find b. Let's use the point (3, 7).
f(x) = mx + b
7 = (1/2)(3) + b
b = 11/2

Now we can write the equation
f(x) = (1/2)x + 11/2

Plugging in x = 7 we find that f(7) = 9. n = 9

Answer 2

Answer:

Option C. 13

Step-by-step explanation:

Since f(x) is a linear function then we can rewrite the function in the form of an equation y = mx + c

where m is the slope of a line.

Since line passes through two points (3, 7), (9, 16)

Therefore m = (16 - 7)/(9 - 3) = 9/6 = 3/2

Now we know a point (16, 26.5) also lie on the line so by putting the values of m, x, and y in the equation.

y = 3x/2 + c

26.5 = 3×16/2 + c

c = 26.5 - 24 = 2.5

So the equation is y = 3x/2 + 5/2

y = 1/2(3x + 5)

If a point (7, n) lies on the line then

n = 1/2(3×7 + 5) = 1/2(21 + 5) = 26/2 = 13

Therefore n = 13 is the answer.