He line of symmetry for the quadratic equation y = ax 2 - 8x - 3 is x = 2. What is the value of "a"? A. -2
B. -1
C. 2

9514 1404 393

  C. 2

Step-by-step explanation:

When the coefficients of the standard-form quadratic are a, b, and c, the equation of the line of symmetry is ...

  x = -b/(2a)

Solving for 'a', we find ...

  a = -b/(2x)

For the given values b=-8 and x=2, the value of 'a' is ...

  a = -(-8)/(2·2) = 8/4 = 2

The value of "a" is 2.

d. 24+-0.114

step-by-step explanation:

the question requires us to calculate the approximate 95% confidence interval for the mean number of ounces of ketchup per bottle in the sample given the following statistics;

sample mean = 24

standard deviation, σ = 0.4

sample size , n = 49

the confidence interval for a population mean is calculated using the formula;

sample mean ± z-score*(σ/sqrt(n))

the z-score associated with a 95% confidence interval, from the standard normal tables, is;

1.96

substituting these values into the formula;

24 ± 1.96*(0.4/7)

= 24 ± 0.112

from the alternatives given, choice d is closest to the above expression;