Ok so ..  the first answer is 
-2x + 18 =2 
Move the constant to the right 
-2x =2 - 18
Calculate the difference 
-2x = -16
Divide both sides of the equation by -2
And that’s how I got x=8
The other one is x - 6y = -4 
X= 6y - 4 
Move the variable to the left hand side by adding it’s opposite to both sides 
X - 6y = 6y - 4 - 6y 
Since two opposites add up to zero,remove them from the expression 
And that’s how x - 6y = -4