1/8, 7/2, 5/6, 10/3
just swap numerator and denominator for each
14x + 10y = 72
14x + 4y = 96
6y = -24
6 6
y = -4
14x + 10y = 72
14x + 10(-4) = 72
14x - 40 = 72
+ 40 + 40
14x = 112
14 14
x = 8
(x, y) = (8, -4)
Answer:
The probability that seven or more of them used their phones for guidance on purchasing decisions is 0.7886.
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Step-by-step explanation:
<em>The question is incomplete:</em>
<em>What should I buy? A study conducted by a research group in a recent year reported that 57% of cell phone owners used their phones inside a store for guidance on purchasing decisions. A sample of 14 cell phone owners is studied. Round the answers to at least four decimal places. What is the probability that seven or more of them used their phones for guidance on purchasing decisions? </em>
We can model this as a binomial random variable, with p=0.57 and n=14.

a) We have to calculate the probability that seven or more of them used their phones for guidance on purchasing decisions:




I believe 25 has to be added as
(x*5)^2 = x^2 + 10x + 25