math help. PLEASE!!?

Question

1.Which of the following is not true for all real numbers a, b, and c?
A.If a > b, then b < a.
B.If a > b, then a - c > b - c.
C.If a < b, then ac < bc.
D.If a > b and b < c, then a < c.

2. Specify the union of the given sets.
{-1, 0, 1}
{0, 1, 2, 3}

A.{-1, 0, 2, 3}
B.{-1, 0, 1, 2, 3}
C.{0, 1}
D.{-1, 0, 1, 2}

Answer 1

1) The answer COULD be c or d
c) if a is 3 and b is 6 -3>-6 (c is -1)
d) a=4 b=3 c=3.5
2. the union is b

Answer 2

1.) D

Answer 3

1. C is false. 1 < 2, but if c = -1,
then -1 > -2.
D is also false.
For example, 2 > 1. Take c = 1.5

2. Just put the elements together, counting
each element only once.
The union of the 2 sets is {-1,0,1,2,3}, answer B.

Answer 4

2) b

Answer 5

It's not just D

C isn't necessarily true either. Real numbers can still be negative

suppose a = -2 and b = 3 and c = -4

Then ac = +8 and bc = -12

ac is greater then bc

Answer 6

Number 1 is definitely D but number 2... ???

Answer 7

i know question 1 is D but i dont get question 2

Answer 8

1) C,D ( I THINK BOTH IF THAT,S O.K)
2) B

Answer 9

I think one is c or d
two is is b

Answer 10

1.- D
2.- B.