Question 49704
{{{12/21 = (x-5)/x}}} multiply both sides by x and 21
{{{12x = 21x - 105}}} subtract 21x from both sides
{{{-9x = -105}}}  divide both sides by -9
{{{x = (-105)/-9}}}
x = 11 6/9   6/9 = 2/3
so answer B
x = 11 2/3

Pete