Answer:
Step-by-step explanation:
-2 (-x +5y ) + 3 (2x - 6y)
Opening bracket
= 2x - 10y + 6x - 18y
= 8x - 28y
= 4(2x - 7y)
The angle sum identity for cosine says that

because

and

.
Answer:
C. Independent
Step-by-step explanation:
Independent events are events that have no impact on each other.
So, if the occurrence of an event doesn't influence the outcome of another, this means that they are independent because they do not impact each other.
This must mean C is correct because the two events have to be independent.
Answer:
0
Step-by-step explanation:
Amount Of Gram= 500
one fourth of gram in one hour=1/4×500 = 125
in four hours the gram filtered out = 4×125= 500
therefore the amount of gram remaining in the contaminants = 500-500= 0 gram