The only rule to follow is
Divide dividend by divisor and the mention the quotient and things left after remains in place of remainder
Here is a sample

Answer:
48
Step-by-step explanation:
Given,
x = - 1
y = 2
To find : The value of 3x - 4 ⋅ xy² ?
Substitute the given values of x and y in the expression 3x - 4 ⋅ xy².
3x - 4 ⋅ xy²
= 3 ( - 1 ) - 4 ⋅ ( - 1 ) ( 2 )²
= - 3 - 4 ⋅ - 1 ( 4 )
= - 12 ⋅ - 4
= 48
Note : -
When a negative number gets multiplied with a negative, the resulted number is a positive number.
First, what's 3 to the power of 8?
Then what's 3 to the power of 10
Now subtract them by each other for your answer