Answer:
A.
Step-by-step explanation:
Take a look at what happens when squaring either of these...
Notice a couple of patterns.
1. The last term has a positive coefficient. That rules out answer choices C and D.
2. The coefficient of the middle term is either . So what are <em>a</em> and <em>b</em>? <em>a</em> is the square root of the x^2 term and <em>b</em> is the square root of the y^2 term.
The middle coefficient needs to be either +30 or -30. The answer is choice A.
Answer: 0.82
Step-by-step explanation:
The probability of the computer not containing neither a virus nor a worm is expressed as P(∩
) , where P(
) is the probability that the event V doesn't happen and P(
) is the probability that the event W doesn't happen.
P()= 1-P(V) = 1-0.17 = 0.83
P()=1-P(W) = 1-0.05 = 0.95
Since and
aren't mutually exclusive events, then:
P(∪
) = P(
) + P(
) - P(
∩
)
Isolating the probability that interests us:
P(∩
)= P(
) + P(
) - P(
∪
)
Where P(∪
) = 1 - 0.04 = 0.96
Finally:
P(∩
) = 0.83 + 0.95 - 0.96 = 0.82