Question

What is the value of f(2) for the function f(x) = 5x + 3?

Answer 1

plug the x in to the equation

Answer 2

put x=2 and you will get your answer as 13

Answer 3

then solve

Answer 4

f(x) = 5x +3
now the question asks for the f(2)

So u must substitute 2 instead of x in f(x) ....
f(x) contain only one term which include x - i.e "5x"
now substitute 2 instead of x in "5x"

and u will get a expression like this
5x +3 -----> (5*2) +3 = 13
yep! , that's the value of f(2) ..... Did u get it now ?

Answer 5

kinda can you show me another one so i can understand it
What is the value of g[f(5)] for the functions f(x) = 2x + 1 and g(x) = 2x - 5?

Answer 6

Let's start with f(x)...
f(x) = 2x + 1
the question requests f(5) so....
substitute 5 instead of x in f(x)
2x + 1 -----> (2*5) +1
which is 11

so f(5) = 11

Now let's move to the second part
g(x) = 2x - 5

now the question asks for g[f(5)]
now substitute f(5) instead of x in g(x)

2x - 5 ------------> [2*f(5)] -5
since f(5) = 11
[2*f(5)] -5 = (2*11) -5 = 17
yep that's it!
g[f(5)] = 17