Answer:
the solutions are 1 and -7
Step-by-step explanation:
first add 14 to both sides
2x²+12x=14
2(x²+6x)=14 now find half of 6x and square it, then add it to both sides
2(x²+6x+9)=14+18(9 was multiplied by 2)
no factor
2(x+3)²=32 divide both sides by 2
(x+3)²=16 square root both sides
x+3=+/- 4 subtract 3
x= 4-3=1
x= -4-3=-7
Answer:
The variance for the number of correct answers is 2.8 questions
Step-by-step explanation:
The number of correct answers follows binomial distribution, in which we have:
- n identical and independents events: the 15 questions
- two possibles results that we call success and fail: The answer is correct and the answer is incorrect
- probability p of success and 1-p of fail. Probability 1/4 of get the answer correct and probability of 3/4 of get the answer incorrect. This probabilities are calculated on that way because every question have 4 possible answers and one of which is correct.
So, the variance for a variable x that follows a Binomial distributions is:
V(x)=n*p*(1-p)
Then, the variance for the number of correct answers is:
V(x)=15*(1/4)*(3/4) = 2.8125 ≈ 2.8
Because n is equal to 15, p is equal to 1/4 and (1-p) is equal to 3/4.
Answer:
D: {9, 21, 33}
Step-by-step explanation:
Ken worked 2, 8 and 14 hours on 3 separate days.
For working 2 hours, his earnings were f(2) = 2(2) + 5, or 9;
For working 8 hours, his earnings were f(28) = 2(8) + 5, or 21; and
For working 14 hours, his earnings were f(14) = 2(14) + 5, or 33
Thus, the range of this function for the days given is {9, 21, 33} (Answer D)
Answer:
the correct answer is j=12+7
