Answer:
That sign means raise to power e.g 5^2.
5 in 2 places which is 25.
Also meaning 5× 2= 25
Answer:
Mean = 1.57
Variance=0.31
Step-by-step explanation:
To calculate the mean and the variance of the number of successful surgeries (X), we first have to enumerate the possible outcomes:
1) Both surgeries are successful (X=2).

2) Left knee unsuccessful and right knee successful (X=1).

3) Right knee unsuccessful and left knee successful (X=1).

4) Both surgeries are unsuccessful (X=0).

Then, the mean can be calculated as the expected value:

The variance can be calculated as:

f(x) - g(x)
=> (3x² + x - 3) - (x² - 5x + 1)
=> 3x² + x - 3 - x² + 5x - 1
=> 3x² - x² + x + 5x - 3 - 1
=> 2x² + 6x - 4
If the interst rate is 2% per year and she paid it back after 3 years , it means she paid an extra 6% of $2000 just in interests.
Now we just need to find how much 6% is and add to 2000.
to discover the value of 6% of 2000 we can divide it by 100 ( to find 1%) and then multiply it by 6 ( to find 6%) :
2000 ÷ 100 = 20
1% = 20
6% = 20 × 6
6% = 120
Now add 120 to 2000 to find out how much she paid in total:
2000 + 120 = 2120
Awnser : She paid the total of $2120 over 3 years
I hope you understood my brief explanation. And please consider marking this awnser as Branliest. Thank you ! :)