Respuesta :

VirαtKσhli

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