Respuesta :
Given :-
- f(x) = 2x + 5
To Find :-
- The input when output is 21 .
Answer :-
The given function is ,
- f(x) = 2x + 5
Substitute f(x) = 21 ,
- 21 = 2x + 5
- 21 - 5 = 2x
- 16 = 2x
- 16/2=x
- x = 8
Answer:
input = 8
Step-by-step explanation:
x is the input and f(x) is the output
Given f(x) = 2x + 5 and f(x) = 21 , then equating gives
2x + 5 = 21 ( subtract 5 from both sides )
2x = 16 ( divide both sides by 2 )
x = 8
That is the input is 8