Question

3x+4x+3 (8x+4)/31 - 12

Answer 1

3x+4x+24x+12/31-12
31x+12-12/31
31x/31
0

Answer 2

$3x + 4x + \frac{3 \times (8x + 4)}{31} - 12 = 3x + 4x + \frac{24x + 12}{31} - 12= \frac{93x + 4x + 24x + 12 - 12}{31} = \frac{121}{31}$
Primeiro apliquei a propriedade distributiva