Question

2. Evaluate f(x) = 3x+5/x-1
at x = 3

Answer 1

Let f(x) = ax + b

Then

f(x + 1) = a(x + 1) + b

= ax + a + b

Hence, a = 3, and a + b = 5, b = 2

f(-2) = 3(-2) + 2

= -6 + 2

= - 4

f(2x) = 3(2x ) + 2

= 6x + 2