Question

Dada a função f : R → R por f(x) = x + 5,
determine o valor de f(2) + f(3) – f(1).

Answer 1

$f(x)=x+5\\\\f(2)=2+5\\\\f(3)=3+5\\\\f(1)=1+5\\\\\\f(2)+f(3)-f(1)=(2+5)+(3+5)-(1+5)\\\\f(2)+f(3)-f(1)=2+5+3+5-1-5\\\\f(2)+f(3)-f(1)=9$