Question

What is the output of the function f(x) = x + 21 if the input is 4?

Answer 1

f(x) = x + 21
f(4) = 4 + 21
= 25

Answer 2

For the input x = 4 , the output of the given function is, 25

Explanation:

Function rule states that a function is when one variable or term depends on another according to a rule.

Also, there is a special relationship between the two variables of the function where each value in the input applies to only one value in the output.

i,e y= f(x) where x is the input and y is the value of the function or, the output.

Given the function: f(x) = x+21 ......[1]

If input is 4 (i.e, x=4)

then, solve for the output of the function.

By definition of function rule;

Substitute the value of x = 4 in [1] we get;

f(4) = 4 + 21 = 25

Therefore, the output of the function is, 25