Ineed to know the answer to this problem:
on day 1, the manager of a bakery has 480 pounds of flour. the amount of flour remaining changes by -40 pounds each day. at the end of which day will the manager have less than 140 pounds of flour?
can you also tell me how i can show my work ?

Let us assume the day after which the manager will have 140 pounds of flour = x
Then
40x + 140 = 480
40x = 480 - 140
40x = 340
x = 340/40
   = 8.5 days
So from the above deduction we can see that after 8.5 days the manager will have 140 pounds of flour left. The answer to the question will then be that after 9 days the manager will have less than 140 pounds of flour and it can be seen from the above deduction.

C. expression because any expression or equation may contain more than one variable

The american colonies would have been ruled by a king.