The answer should be the directrix because k represents the y-value of the vertex, and for this questions the parabola is probably facing upward, so the directrix is under the vertex.
Answer:
Solving the equation
using quadratic formula we get 
Step-by-step explanation:
We need to solve the equation
using quadratic formula.
The quadratic formula is:

where a=1, b=-8 and c=41
Putting values in formula and finding x

So, Solving the equation
using quadratic formula we get 
This question is about compound interest, but since the interest is such a small number you can use what you know about simple interest to eliminate some answers.
You can immediately eliminate choice A as a clunker, since it is less than the original amount in the account.
Consider what the amount of interest would be if you make the rate much larger than the original rate, say 10%, or 0.1:
$6,500 × 0.1 = $650
If this amount were added to the original amount each year for two years, the total would be:
$6,500 + $650 + $650 = $6,500 + $1,300 = $7,800
This is an over-estimate for the information given, and since choices C and D are even greater than this over-estimate, they can be eliminated. That means choice B is the correct answer.
Answer:
∠ B = 85°
Step-by-step explanation:
the inscribed angle B is half the measure of its intercepted arc AC , then
∠ B =
× 170° = 85°
Answer:
c: f(x) = 2(4^x)
Step-by-step explanation:
the table shows that the function is exponential rather than linear.