8 x 64 = (8 x 60) + (8 x 4)=
Answer:
Part a
For the given study, the explanatory variable or independent variable is given as regularity or frequency of exercise. This variable is classify as categorical variable because variable is divided into two categories such as whether participant exercise 5 or more days a week or not.
Part b
For the given study, the response variable or dependent variable is given as frequency of colds. This variable is classified as quantitative variable because we measure the quantities or frequency of number of colds.
Part c
A confounding variable for this research study is given as incidence of upper respiratory tract infections that provides an alternative explanation for the lower frequency of colds among those who exercised 5 or more days per week, compared to those who were largely sedentary. This confounding variable is categorical in nature.
D is correct for this problem
Answer:
b. The system is not in echelon form because the system is not organized in descending "stair step" pattern so that the index of the leading variables increases from the top to bottom.
Step-by-step explanation:
The given linear system has a equation which is not in echelon form. The echelon is a system which divides the data into rigid hierarchal groups. The given linear equation in not in echelon form as the leading variables are increased from top to bottom indicating descending stair step pattern.
Answer:
length = 5
width = 9
Step-by-step explanation:
V = lwh
let 'x' = length
let '4+x' = width
9 = height
405 = 9x(4+x)
405 = 36x + 9x²
this is a quadratic equation: 9x² + 36x - 405 = 0
factor out a 9 to get:
9(x² + 4x - 45) = 0
9(x-5)(x+9) = 0
one root is 5 and the other is -9
since distance cannot be negative we use 5 as the length and 9 is the width
