Answer:
(a) 
(c) 
Step-by-step explanation:
(a) To find verify the answer we need to multiplying the equation

Thus, this statement is true.
(b) To find verify the answer we need to multiplying the equation 

Hence, the given statement is false.
(c) To find verify the answer we need to multiplying the equation 

Hence, the given statement is true.
(d) To find verify the answer we need to multiplying the equation

Hence, the given statement is false.
Answer:
Option C
Step-by-step explanation:
same logic as in 2D problems. if C wasn't true, then the two planes couldn't be parallel
Answer:
The answer is B (2).
Step-by-step explanation:
No because if you subtract -10-2 you get -12 and you only have a negative answer