# Function Notation Formula

Functions or Functional Notations are referred by the letter ‘f’ and written as f(x), sometimes in the form of g(x), h(a) etc.

### Solved Examples

Question 1: Represent y = $x^{2}$ + 4x + 1 using function notation and find the value of y at x = 3 ?

Solution:

Given function is,
y = $x^{2}$ + 4x + 1
By using function notation,
f(x) = $x^{2}$ + 4x + 1
Value of y at x = 3 means f(3).
So, f(3) = $3^{2}$ + 4$\times$3 + 1 = 9 + 12 + 1 = 22

Question 2: Represent the given function y = $x^{3}$ – 4x using function notation and find the value of y at x = 2 ?

Solution:

Given function is,
y = $x^{3}$ – 4x
By using function notation it become,
f(x) = $x^{3}$ – 4x
The value of y at x = 2 means f(2).
Therefore, f(2) = $2^{3}$ – 4 $\times$ 2 = 8 -8 = 0
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