Answer:
Let f(x) and g(x) be the function then;
[tex](f+g)(x) = f(x)+g(x)[/tex]
Given the functions:
[tex]f(x) = 2x+21[/tex]
[tex]g(x) = x-24[/tex]
Solve for : [tex](f+g)(3)[/tex]
[tex](f+g)(3) = f(3)+g(3)[/tex] .....[1]
Put x = 3 in f(x) and g(x) we have;
[tex]f(3) = 2(3)+21 = 6+21 = 27[/tex]
and
[tex]g(3) = 3-24 = -21[/tex]
Substitute these values in [1] we have;
[tex](f+g)(3) =27 +(-21) = 27-21 = 6[/tex]
Therefore, the value of [tex](f+g)(3)[/tex] is 6
