Question

If the expression 4a-b is divisible by 4 for
any integer a and b, which of the following
MUST be true:
I. a is even
II. b is divisible by 4
III. b is positive
a. I only
b. II only
c. III only
d. I and II only
e. II and III only

Answer 1

is divisible by 4

Answer 2

b*

Answer 3

what about the other choices?

Answer 4

i dont think they r necesary
the only condition that Must be true always is the (b)

Answer 5

the second condition *

Answer 6

ok *necessary is key right?

Answer 7

no it does not matter it is just common sense

Answer 8

just replace some numbers
for example
if b=4
and a is odd for example 3
we have
2*3 -4
12-4
8
and 8 is divisible by 4

Answer 9

yeah that makes since
well thank you for the help :)