Answer:
3x + 0.8y
General Formulas and Concepts:
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
Distributive Property
<u>Algebra I</u>
Step-by-step explanation:
<u>Step 1: Define</u>
(-4x + 4.2y) - (-7x + 3.4y)
<u>Step 2: Simplify</u>
- [Distributive Property] Distribute negative:                                                    -4x + 4.2y + 7x - 3.4y
- Combine like terms (x):                                                                                    3x + 4.2y - 3.4y
- Combine like terms (y):                                                                                    3x + 0.8y
 
        
             
        
        
        
This is 10.5^2 10.5 is the base and 2 is the exponent. The area is 110.25 square inches.
        
             
        
        
        
If angle of a sector is 115 
the central angle would be 115 also
as the arc measure is equal to the measure of its central angle
        
             
        
        
        
The greatest common factor of 4 and 10 is 2
        
             
        
        
        
Answer:
a) Decrease
b) New mean = 78.43
c) Decrease                         
Step-by-step explanation:
We are given the following in the question:
Total number of students in class = 28
Average of 27 students = 79
Standard Deviation of 27 students = 6.5
New student's score = 63
a) The new student's score will decrease the average.
b) New mean


New mean =

Thus, the new mean is 78.43
c) Since the new mean decreases, standard deviation for new scores will decrease.
This is because the new value is within the usual values i.e. within two standard deviations of the mean. So, this wont cause a lot of variation as this value will be closer to already available data values. Also number of observations (n) in the denominator is increasing. Based on both these points we can conclude that standard deviation will decrease
Formula for Standard Deviation:
 
  
where  are data points,
 are data points,  is the mean and n is the number of observations.
 is the mean and n is the number of observations.