Answer:
(a) 4
(b) 4 * (7+3)
Step-by-step explanation:
(a) Let's first start by prime factorizing (finding the prime factors) 28 and 12:
12: 2*2*3
28: 2*2*7
We can see here they both share a common factor of 2*2, which is 4, therefore the GCF is 4.
(b) Factor a 4 out from the equation:

This gives us:
4 * (7+3)
Act like it's a rectangle. The height is 10 because 7+3=10 and the length it 27. Multiply them for the are and you get 270 in. Then multiply 6x7=42 because that's the are of the space that is missing from the imaginary rectangle. Multiply by 2 (84 in.) because there are 2 missing spaces and subtract from 270= 186 inches is your answer.
Answer:
The value is Approximately 56
2/7 is the probability that the first satellite sends a weak signal. That leaves 6, one of which sends a weak signal. So the probability that the second also sends a weak signal is 1/6. Combine these and we get 2/7×1/6=1/21.