Respuesta :

a. Let x equal amount of people per week leaving
 63=7x
 63/7=7x/7
9=x
so -9

b. because each share went down by 10 dollars multiply 10 dollars by 50 shares and you get the total amount of value changed.
50*10=500
the value changed by $-500   
$-500 is the correct answer :)