Question

f( x) = 3(x + 1) + 4(x - 1)

Answer 1

f(x)=3x+3+4x-4
f(x)=7x-1
Caso queira encontrar a raiz, igualando a zero, o valor será 1/7

Answer 2

f(x) = 3(x+1) + 4(x-1)

f(x) = 3x + 3 + 4x - 4

f(x) = 3x + 4x + 3 - 4

f(x) = 7x - 1                 ok