Question

If ǀbǀ>= -1 and x=-ǀaǀb, then which of the following is necessarily true?
a) a-xb<0
b) a-xb>=0
c) a-xb>0
d) a-xb<=0

Answer 1

|b|>=-1 means |b|>=0
because || this gives values alwys >=0

Answer 2

it can not give values less than zeros

Answer 3

|b|>= -1 is always true, for any b

Answer 4

it can not equal ..>= mean minimum value