He would have 21 before he bought the 10 stamp because 31-10=21
Answer:
see below
Step-by-step explanation:
Find the magnitude (-1)^2 + (sqrt3)^2 = m^2 m = 2
find the angle arctan (sqrt3/-1) = 120 degrees
the cube root would then be
(cos 40 + isin 40)
It could be the first one or the third the others are not actual measuring units
im going with the first one