Question

x/3 + x/5 + 3(x/3 - x/5) +3 ?

Answer 1

$\frac{x}{3} + \frac{x}{5} + \frac{3x}{3} - \frac{3x}{5} +3$
$\frac{4x}{3} - \frac{2x}{5} +3$
$\frac{20x-6x+45}{15} =0$
$\frac{14x+45}{15}=0$
$14x+45=15$
$14x=15-45$
$x= \frac{-30}{14} =- \frac{15}{7}$