Answer:
Option A is correct.
The constant of variation is, 
Step-by-step explanation:
The Direct variation says that:
if a vary directly to b then, the equation is of the form: a = kb where k is the constant of variation.
Given: if y varies directly as x.
By definition of direct Variation:
y = kx where is the constant of variation.
It is also given that: y = -3 and x =2
Solve for k;
-3 = 2k
Divide both sides by 2 we have;

Therefore, the constant of variation is, 
Answer:
True because when you multiply the 2 by everything in the parentheses you get 4x + 6y which is 4x + 6y = 4x + 6y. and when you solve it you'll get 0 = 0
Step-by-step explanation:
Answer:
C = 2πr
Step-by-step explanation:
The circumference of a circle is calculated by the formula here,
C is the circumference of the circle.
r is the radius of the circle.
π is 22/7 or 3.14.
In the given options π is not missing.
Therefore the formula that relates circumference and radius is C = 2πr.
Answer:
1. 6x^2 + 4x - 4y
2. x - 10y.
3. 6x^5
4. 36 a^6 b^8
5. x^2 - 81
6. 9x^2 - 42x + 49
7. 12x^2 +3x - 42
Step-by-step explanation:
1. 3x^2+4x+3x^2-4y
Add the like terms, we get
6x^2 + 4x - 4y
2. (5x-2y)-(4x+8y)
Now distribute the negative sign, we get
5x - 2y -4x -8y
Simplify the like terms, we get
x - 10y.
3. 3x^3(2x)^2
Multiply the numbers and simplify the variables
6x^(3 +2)
6x^5
4. (-6a^3b^4)^2
Now bring the power 2 inside the parenthesis.
-6^2 a^6 b^8
= 36a^6b^8
5. (x+9) (x-9)
x^2 + 9x -9x - 81
x^2 - 81
6. (3x-7)^2
(3x - 7)(3x - 7)
9x^2 - 21x -21x + 49
9x^2 - 42x + 49
7. (3x+6) (4x-7)
12x^2 + 24x -21x - 42
12x^2 +3x - 42
Thank you.