a. By definition of conditional probability,
P(C | D) = P(C and D) / P(D) ==> P(C and D) = 0.3
b. C and D are mutually exclusive if P(C and D) = 0, but this is clearly not the case, so no.
c. C and D are independent if P(C and D) = P(C) P(D). But P(C) P(D) = 0.2 ≠ 0.3, so no.
d. Using the inclusion/exclusion principle, we have
P(C or D) = P(C) + P(D) - P(C and D) ==> P(C or D) = 0.6
e. Using the definition of conditional probability again, we have
P(D | C) = P(C and D) / P(C) ==> P(D | C) = 0.75
Answer: it might be D
Step-by-step explanation: I think so on edge -4 must be factored from -4x^2-7
Answer:

Step-by-step explanation:
By putting the numbers in the given equation,

2x + 3 + 3x = 7x + 9
5x + 3 = 7x + 9
(5x + 3) - 7x = (7x + 9) - 7x
(5x - 7x) + 3 = 9
-2x + 3 = 9
(-2x + 3) - 3 = 9 - 3
-2x = 6

-x = 3
x = -3
Therefore, our equation is correct which has a negative result.
In place of 6 if we use 8, value of x will be negative again.