Answers:
Kinetic Energy Formula: 
Potential Energy Formula: 
Explanations:
For KE:
Kinetic energy is directly proportional to the mass of the object and to the square of its velocity. If the mass has units of kilograms and the velocity of meters per second, the kinetic energy has units of kilograms-meters squared per second squared.
For PE:
In the above equation, m represents the mass of the object, h represents the height of the object and g represents the gravitational field strength (9.8 N/kg on Earth) - sometimes referred to as the acceleration of gravity.
1)
Solving from system of equations:
x- amount of 1 cent stamps
y- amount of 33 cent stamps

2)
x- amount of 20 cent stamops
y-amount of 34 cent stamps
From system of equations:
Answer: D.-6 and F.3
Step-by-step explanation:
The given rational number : 
To find : The value of x , where the rational expression becomes equal zero.
Let's check all the options :
A. 7
At x= 7 , 
B. -7
At x= 7 , 
C. 6
At x= 6 , 
D. -6
At x= -6 , 
E. -3
At x= -3 , 
F. 3
At x= 3 , 
Thus, at x= -6 and 3 , the rational expression equals to zero .
So , the correct options are : D.-6 and F.3
D for the 1st
B. For the 2nd
-4,3. For the 3rd
C. The 4th
<. The 5th
>. And the 6th
I think that it would be (-4,-4) when you cross the y axis