I got -2(2x-3) but it should be C.-4x-2
Probability that both roads from a to b are blocked is the product of the individual probabilities, i.e.
P(~ab)=0.25*0.25=0.0625
Similarly
P(~bc)=0.25*0.25=0.0625
Probability that EITHER one or both of ab and bc are blocked is the sum of the probabilities:
P(~ab ∪ ~bc)=0.0625+0.0625=0.125
(recall that one cannot travel from a to c if either ab or bc is blocked.)
Therefore the probability that there exists an open route from a to c
= P(ac) = 1-P(~ab ∪ ~bc)
= 1 - 0.125
=0.875
When you add, you subtract the exponents. When you divide, you subtract the exponents.
When you have multiplication and division in one expression, you do it from left to right.
7^2 times 7^5 = 7^ (2+5) = 7^7
7^7 times 2^2 / 7^3 = 7 ^(7 - 3) times 2^2
7^4 times 2^2 times 2^6 = 7^4 times 2^(2+6) = 7^4 times 2^8
Put it in a calculator.
614656.
That is the answer, but you didn't include the "which of the following", so I guess you'll have to put each value in the calculator to find out!
If the 7^3 times 2^6 is in parenthesis, then the answer is 150.0625.
8: 20
9: 90
I am so sorry if this is wrong. I am not good at this type of things