Answer:
Option C. 13
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.