Answer:


Step-by-step explanation:
For this case we have the following data given:
2.3 3.1 2.8
1.7 0.9 4.0
2.1 1.2 3.6
0.2 2.4 3.2
Since the data are assumedn normally distributed we can find the standard deviation with the following formula:

And we need to find the mean first with the following formula:

And replacing we got:

And then we can calculate the deviation and we got:

Answer:
r = 105
Step-by-step explanation:
Given quadratic equation:
x² − 9x − 6
Quadratic formula is given by:
(-b ± √b² - 4ac) ÷ 2a
For the equation: x² - 9x - 6
a = 1, b = -9 and c = -6
Substitute in the quadratic formula:
(-b ± √b² - 4ac) ÷ 2a
(-(-9) ± √(-9)² - 4(1*-6)) ÷ 2*1
= 9 ± √105 / 2
The solution of x² − 9x − 6 is expressed as 9 plus or minus the square root of r, all over 2
Therefore, the value of r is 105
Answer:
<h3>Add to eliminate y.</h3>
Step-by-step explanation:
Given the equations
-9x + y = 71.... 1
-x - y = -1 .... 2
Using elimination method we can eliminate y first since they have the same coefficient.
To do that we will need to add up both equations. We are adding because the coefficient of y in both equations has different signs. If they have the same sign, we would have subtracted.
<em>Hence the correct option in this case is to add to eliminate y.</em>
Answer:
qn 10. 15mn² - 23m²n +4m³
Step-by-step explanation:
1. distribute 4m through the parenthesis
8mn² - 12m²n + 4m³ - 2n(5m² - 3nm) + nm(n-m)
2. use the commutative property to reorder the terms
8mn² - 12m²n + 4m³ - 2n(5m² - 3mn) + mn(n - m)
3. distribute -2n through the remaining parenthesis
8mn² - 12m²n + 4m³ -10m²n + 6mn² + mn² - m²n
4. collect like terms
8mn² + 6mn² + mn² - 12m²n - 10m²n - m²n + 4m³
5. complete bodmas
15mn² - 23m²n +4m³
that's is how you do it so the answer is
15mn² -23m²n + 4m³