How many roots does the relation y = 4x² - 20x + 25 have? (2 marks)
1 answer:
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Answer:
b. 4x^2 + 3x - 6
Step-by-step explanation:
The values of f(x) for the extremes of x are more positive than the value of f(x) for the middle x, so we know the parabola opens upward. That eliminates choice D.
It is probably easiest to evaluate the other expressions to see which one matches the given f(x) values. For the purpose, it is usually easier to use the Horner form of the equation.
a. f(-2) = (3(-2) +4)(-2) -6 = -2(-2) -6 = -2 ≠ 4
b. f(-2) = (4(-2) +3)(-2) -6 = -5(-2) -6 = 4 . . . . matches the given data point
c. Because (b) matches, we know this one will not.
The appropriate choice is B.
Answer:
0.999987
Step-by-step explanation:
Given that
The user is a legitimate one = E₁
The user is a fraudulent one = E₂
The same user originates calls from two metropolitan areas = A
Use Bay's Theorem to solve the problem
P(E₁) = 0.0131% = 0.000131
P(E₂) = 1 - P(E₁) = 0.999869
P(A/E₁) = 3% = 0.03
P(A/E₂) = 30% = 0.3
Given a randomly chosen user originates calls from two or more metropolitan, The probability that the user is fraudulent user is :
= 0.999986898 ≈ 0.999987