To help you understand this, it is helpful to create a sample set of data:
__,__,__,(Q1 is here)__,__,__,(median is here)__, __,__,(Q3is here)__,__,__
A. The first 3 lines are 3 pieces of data in the first quartile.
B. here are 6 pieces of data between the 1st and 3rd quartiles.
D. There are 3 pieces of data in the upper quartile.
Step-by-step explanation:
let's look at the full numbers under the square roots when bringing the external factors back in :
sqrt(9×9×2) - sqrt(3×3×7) + sqrt(8) - sqrt(28)
and let's present these numbers as the product of their basic prime factors
sqrt(3×3×3×3×2) - sqrt(3×3×7) + sqrt(2×2×2) - sqrt(2×2×7)
now we see that we have 2 pairs of square roots : 1 pair ends with a factor of 2, and one pair with a factor of 7.
let's combine these
sqrt (3×3×3×3×2) + sqrt(2×2×2) - sqrt(3×3×7) - sqrt (2×2×7)
and now we move the factors of 2 and 7 back out in front (of course, we need to apply the square root on these factors) :
9×sqrt(2) + 2×sqrt(2) - 3×sqrt(7) - 2×sqrt(7) =
= (9+2)×sqrt(2) - (3+2)×sqrt(7) = 11×sqrt(2) - 5×sqrt(7)
and that is the first answer option.
Answer:
9. x=-6, y=0
10. x=-9, y=-10
11. x=3, y=-1
Step-by-step explanation:

Multiply the first equation by 2.

Add the equations.


We figured out x now we have to figure out y. To figure out y plug in x into any equation.




Your answer is x = -6 and y = 0 for number nine.

Change the signs of the second equation becuase 3y and 3y are both positive. We need one of them to be negative.

Add them.


Now we have to figure out y.




x=-9 and y=-10 is your answer to number ten.








x=3 and y=-1 is the answer to number eleven. I hope this helps! Let me know if I got anything wrong.
The errors are that she is just multiplying incorrectly.
10* 1.75 = 17.5
100* 1.75= 175
1000* 1.75 = 1750
When you are multiplying by tens (hundreds and thousands are also considered tens since they are just 10*10 and 10*10*10), you should just be moving the decimal place forward one place.
This goes back to very basic math when you are learning place values.