I hope this helps you
2x^2-4x+7=0 a=2 b=-4 c= 7
disctirminant =b^2-4ac
disctirminant =(-4)^2-4.2.7
disctirminant = 16-56= -40
x=-b+square root of disctirminant ÷2a
x=4+2square root of (-10)/4
x=2+square root of (-10)/2
x'=4 -2 square root of (-10)/4
x'=2 -square root of (-10)/2
Answer:
option (D) 16.5
Step-by-step explanation:
Data provided:
Sleep time of , X = 15.9 is at the 10th percentile
Standard deviation, σ = 0.5 hour
also,
10th percentile of normal distribution is
Z = F⁻¹(0.10)
or
Z = - 1.28 (Using Standard Normal distribution)
Now,

or
X = μ + ( σ × Z )
or
μ = X - ( σ × Z )
on substituting the respective values, we get
μ = 15.9 - 0.5 × (-1.28)
or
μ = 16.5
Hence, the correct answer is option (D) 16.5
Step-by-step explanation:
Given that,
A motor boat travels 60 miles down a river in 3 hours but takes 5 hours to return upstream,
We know that,
Speed = distance/time
The rate while moving downstream
The rate while moving upstream 
The rate of the boat in still water is the average of these:

The rate of the current is the difference between the boat speed and actual speed = 16 mph - 12 mph = 4 mph
Hence, this is the required solution.
Answer:
The total amount received is: $1906650
Step-by-step explanation:
Given
--- initial
--- rate
--- time
Required
Determine the total amount at the end of 29 years
The given question is an illustration of geometric progression, and we are to solve for the sum of the first n terms
Where 


Express percentage as decimal


The required is the calculated using:

So, we have:





<em>The total amount received is: $1906650</em>
Answer: The range is y ≥ 3.
Step-by-step explanation:
When we have an equation:
y = f(x)
The range is the set of the possible values of y.
In this case, we have:
y = f(x) = 2*x^2 - 20*x + 53
This is a quadratic equation, and the leading coefficient is positive. This means that the arms of the graph will open upwards.
Then the minimum value of y will be the vale at the vertex.
We know that for a quadratic equation of the form:
a*x^2 + b*x + c
The vertex is at:
x = -b/2a
Then in this case, the vertex will be at:
x = -(-20)/(2*2) = 20/4 = 5
Then the smallest value of this function will be:
f(5) = 2*5^2 - 20*5 + 53 = 3
This is the smallest value that y can take, and y can take any value greater than 3.
Then the range can be written as:
y ≥ 3.