Question

A function f(x) is linear and has a value of 29 at x = -2 and 39 at x = 3. Find its value at x = 5.

• A. 59
• B. 45
• C. 43
• D. 35

Answer 1

The correct option is C 43

f(x) is linear

Let f(x) = ax + b

f(-2) = 29

$\Rightarrow$ -2a + b = 29 ....(i)

f(3) = 39

$\Rightarrow$ 3a + b = 39 ....(ii)

From (i) and (ii)

a = 2, b = 33

$\Rightarrow$ f(x) = 2x + 33

f(5) = 2(5) + 33 = 43