Question

Given that f(x) = x + 3 a) Find f(2)

Answer 1

${ \qquad\qquad\huge\underline{{\sf Answer}}}$

Here we go ~

In the above question, it is given that :

$\qquad \sf \boxed{ \sf f(x) = \frac{x + 3}{2} }$

A.) Find f(2) :

$\qquad \sf \dashrightarrow \: f(2) = \dfrac{2 + 3}{2}$

$\qquad \sf \dashrightarrow \: f(2) = \dfrac{5}{2}$

or

$\qquad \sf \dashrightarrow \: f(2) = 0.5$

B.) Find ${ \sf {f}^{-1}(x) }$ :

$\qquad \sf \dashrightarrow \: let \: y = f (x)$

so, we can write it as :

$\qquad \sf \dashrightarrow \: y = \dfrac{x + 3}{2}$

$\qquad \sf \dashrightarrow \: 2y = x + 3$

$\qquad \sf \dashrightarrow \: x = 2y - 3$

Now, put x = ${ \sf {f}^{-1}(x) }$, and y = x and we will get our required inverse function ~

$\qquad \sf \dashrightarrow \: f {}^{ - 1}(x) = 2x- 3$

C.) Find ${ \sf {f}^{-1}(12) }$ :

$\qquad \sf \dashrightarrow \: f {}^{ - 1}(12) = 2(12)- 3$

$\qquad \sf \dashrightarrow \: f {}^{ - 1}(12) = 36- 3$

$\qquad \sf \dashrightarrow \: f {}^{ - 1}(12) = 33$