Question

Seja f(x) = $3^{x}$
Determine: f( x + 1) + f( - x + 4) = 36

Answer 1

f(x+1) = $3^{x+1}$
f(-x+4) = $3^{-x+4}$

$3^{x+1}$ + $3^{-x+4}$ = 36

x=2 pois: $3^{2+1} + 3^{-2 +4} = 3^{3} + 3^{2} = 27+9 = 36$

=)