This link to a video will help
https://youtu.be/k3RwfEvqrB8
Answer:
The correct answer is the last option, that is, 
Step-by-step explanation:
We have been given that the first runner has $112 in savings, received a $45 gift from a friend, and will save $25 each month. Therefore, amount of money in the account of first running after m months will be: 
We have been given that the second runner has $50 in savings and will save $60 each month. Therefore, amount of money in the account of second running after m months will be: 
In order for amount of money to be equal in accounts of both the runners, we set up:

Upon rewriting the left hand side using commutative law, we get:

Therefore, we can see that the last option is the correct answer.
Answer: 2.76 g
Step-by-step explanation:
The formula to find the standard deviation:-

The given data values : 560 g, 562 g, 556 g, 558 g, 560 g, 556 g, 559 g, 561 g, 565 g, 563 g.
Then, 
Now, 
Then, 
Hence, the standard deviation of his measurements = 2.76 g
Answer:
A. Increase by 2
Step-by-step explanation:
Given that a fitted multiple regression equation is

This is a multiple regression line with dependent variable y and independent variables x1, x2, x3 and x4
The coefficients of independent variables represent the slope.
In other words the coefficients represent the rate of change of y when xi is changed by 1 unit.
Given that x3 and x4 remain unchanged and x1 increases by 2 and x2 by 2 units
Since slope of x1 is 5, we find for one unit change in x1 we can have 5 units change in y
i.e. for 2 units change in x1, we expect 10 units change in Y
Similarly for 2 units change in x2, we expect -2(4) units change in Y
Put together we have
change in y
Since positive 2, there is an increase by 2
A. Increase by 2