Answer:
x = 45
y = 7
Step-by-step explanation:
To obtain the value of x and y, do the following:
√7 – 3√5
Rearrange
– 3√5 + √7
Multiply through by –1
3√5 – √7 ... (1)
Express 3√5 as a single surd
3√5 = √(3 × 3 × 5)
3√5 = √45
Replace 3√5 with √45 in equation 1
3√5 – √7
√45 – √7
Comparing
√45 – √7 and √x – √y i.e
√45 – √7 = √x – √y
x = 45
y = 7
Answer:
a) The modal class for this case represent the class with the highest frequency
And for this case would be
with the highest frequency 8
b) 
Step-by-step explanation:
Part a
The modal class for this case represent the class with the highest frequency
And for this case would be
with the highest frequency 8
Part b
For this case we need to find the mid point of each interval:
Interval Midpoint Frequency
18-20 19 3
20-22 21 2
22-24 23 7
24-26 25 8
And we can find the sample mean with this formula:

And replacing we got:

Note that the formula for the circumference of a circle is πd, while the formula for the area of a circle is πr².
π≈3.14
A. C=πd
Simply plug in the numbers into the formula.
Diameter=Radius*2
17*2=34
C=34(π)
B. (π)(5²)
Plug in the numbers into the formula. Remember that half of the diameter is the radius.
C. (π)(4.5)
There are two possible formulas that could be used to calculate the circumference of a circle: πd and 2πr.
The expression above is simply multiplying the circle's radius times pi. Therefore, it is not a method that could be used to find the circumference of a circle.
D. (π)(6.5²)
Remember that the formula for calculating the area of a circle is πr².
Half of the diameter is 6.5 (13.5/2=6.5). 6.5 cm. is the radius. Now just plug the numbers into the formula.
(π)(6.5²)
Therefore, the last answer choice is the correct answer.
The Value of X is 10.
KhanAcademy.org has some great explanation videos on their website and they have a YouTube channel.
Here is an explanation for the answer.