Answer:
An unknown variable by reversing the process used to form the original equation.
Step-by-step explanation:
The opposite process rule says to solve for - an unknown variable by reversing the process used to form the original equation.
If an equation indicates an operation such as addition, subtraction, multiplication, or division, solve for the unknown variable by using the opposite process.
For example:
Lets say we have to find 
Here 25 is subtracted from both sides of the equation to isolate x.

we get x = 10
Check this : 
Answer:
15 bags
Step-by-step explanation:
3 = 12/4
3 3/4 = 3+3/4 = 12/4 + 3/4 = (12+3)/4 = 15/4
(15/4) ÷ (1/4) = 15
Amount of oil sandi has = 2 1/3 * 12
= 7/3 * 12 = 7*4 = 28 quarts
25/80 + 24/80 = 49/80. 16 and 20 both go into 80. !6 goes in 5 times so you multiply 5 by 5. 20 goes into 80 4 times so you multiply 4 by 4. 24/80 + 25/80 = 49/80.
Answer:
B
Step-by-step explanation:
b is correct