Answer: 20
Step-by-step explanation:
By CPCTC,

Answer:
1. 
2. 
Step-by-step explanation:
Given
Variation: inverse Proportion
y = 7, x = 9
Required
- Write an equation connecting y and x
- Find y when x = 21
Given that thee variation is inversely proportional;
This implies that

Convert variation to equation
----------- Equation 1
Where k is the constant of variation
Substitute 7 for y and 9 for x in equation 1

Multiply both sides by 9


Substitute 63 for k in equation 1

Multiply both sides by x


Hence, the equation connecting x and y is 
Solving for when x = 21
Substitute 21 for x in the above equation

Divide both sides by 21


Answer:
<em>The options are not visible enough (See Explanation)</em>
Step-by-step explanation:
Given
x:- 1 || 2 || 3 || 4 || 5
y:- 13 || 22 || 37 || 58 || 85
Required
Determine if the function is quadratic
Calculate the difference between the values of y




<em>The resulting difference are: 9 || 15 || 21 || 27</em>
Next; Calculate the difference between the difference of values of y



<em>The resulting difference are: 6 || 6 || 6</em>
<em>For the function to be quadratic, the above difference must be the same and since they are the same (6), then the function represents a quadratic function.</em>
Answer:
432
Step-by-step explanation:
The answer would be x^2-18x+81. This can be found be writing "(x-9)^2" twice, and distributing. Combine like terms, and you should get this answer.