Answer:

Step-by-step explanation:
A. Scale factor
When you dilate an object by a scale factor, you multiply its line lengths by the same number.
If EF/AB = 13/7, the scale factor is 13/7.
B. Length of EF

C. Area of EFGH
If the lengths in a shape are all multiplied by a scale factor, then the areas will be multiplied by the scale factor squared.
ABCD is dilated by a scale factor of 13/7, so its area is dilated by a scale factor of

The area of its dilated image EFGH is

Answer:
The correct answer is:
In the above example cancer is an independent variable. (b)
Step-by-step explanation:
In order to explain the choice made, let m first explain what independent and dependent variables are:
Independent variable: An independent variable is a variable that is under the direct control of the experimenter, and can be changed at will. In this example, the number of cigarettes or amount of tobacco smoked is the independent variable because it can be manipulated at will, to determine the outcome of the dependent variable.
Dependent variable: A dependent variable is a variable that the experimenter sets out to study. The independent variable is not under the direct manipulation of the experimenter but has values that come about as a result of the change of the independent variable. In this example, cancer is the dependent variable, because it is the result of the manipulation of the amount of tobacco.
Therefore, it is not true to say that cancer is the independent variable as seen in option b
Answer:
Females = 17 and males = 23
Step-by-step explanation:
Given that,
Total no of students in the class = 40
Let no. of females = x
No. of males = 6+x
ATQ,
Total students = males + females
40 = x+6+x
40-6 = 2x
34 = 2x
x = 17
Hence, there are 17 females and (6+17= 23) males.
3 x - 7 = 5 x + 13
3 x - 5x = 13 + 7
-2x = 20
x = 20 / -2
x = - 10