-4(x-1)=-3x+13-9-x
-4x+4=-3x+4-x
-4x+4=-4x+4
-4x=-4x
0=0
A leg of a right triangle can never be greater then the hypotenuse
this formula will tell you if it's a valid right triangle

the first two question marks are the legs of the triangle while the one after the = is the hypotenuse.
THE STEPS:




ANSWER:
Answer: 1) The best estimate for the average cost of tuition at a 4-year institution starting in 2020 =$ 31524.31
2) The slope of regression line b=937.97 represents the rate of change of average annual cost of tuition at 4-year institutions (y) from 2003 to 2010(x). Here,average annual cost of tuition at 4-year institutions is dependent on school years .
Step-by-step explanation:
1) For the given situation we need to find linear regression equation Y=a+bX for the given situation.
Let x be the number of years starting with 2003 to 2010.
i.e. n=8
and y be the average annual cost of tuition at 4-year institutions from 2003 to 2010.
With reference to table we get

By using above values find a and b for Y=a+bX, where b is the slope of regression line.

and

∴ To find average cost of tuition at a 4-year institution starting in 2020.(as n becomes 18 for year 2020 if starts from 2003 ⇒X=18)
So, Y= 14640.85 + 937.97×18 = 31524.31
∴The best estimate for the average cost of tuition at a 4-year institution starting in 2020 = $31524.31
Answer:
Here's what I get.
Step-by-step explanation:
1. Representation of data
I used Excel to create a scatterplot of the data, draw the line of best fit, and print the regression equation.
2. Line of best fit
(a) Variables
I chose arm span as the dependent variable (y-axis) and height as the independent variable (x-axis).
It seems to me that arm span depends on your height rather than the other way around.
(b) Regression equation
The calculation is easy but tedious, so I asked Excel to do it.
For the equation y = ax + b, the formulas are

This gave the regression equation:
y = 1.0595x - 4.1524
(c) Interpretation
The line shows how arm span depends on height.
The slope of the line says that arm span increases about 6 % faster than height.
The y-intercept is -4. If your height is zero, your arm length is -4 in (both are impossible).
(d) Residuals

The residuals appear to be evenly distributed above and below the predicted values.
A graph of all the residuals confirms this observation.
The equation usually predicts arm span to within 4 in.
(e) Predictions
(i) Height of person with 66 in arm span

(ii) Arm span of 74 in tall person
