Y=-ax-c/y
I did this really fast in my head so check it first
3(x - 4) = 3x - 12 (expand the brackets)
3x - 12 = 2x + 6
3x = 2x + 6 + 12 (put all of the integers on one side)
3x = 2x + 18 (simplify - collect like terms)
3x - 2x = 18 (put all of the unknowns on one side)
x = 18 (simplify - collect like terms)
Therefore, we know that x is equal to 18, and so the answer is E.
The butterfly method. Multiply then divide
The one of the left isn't too tricky, in the bottom left of it you have 1/2 of 1/4 of the shape, and on the bottom right you have 1/4 of 1/4. Imagine the whole shape was cut up like that bottom right bit into 16 triangles, then you would have three of them shaded (see my diagram).
The one on the right seems like guesswork to me, so I'm sorry if I'm wrong. It look like you just have to use your eyes to work out how much of the bottom half of the shape is shaded: looks like 1/16 to me (i.e. you can draw four of those along and four down, again, see my diagram.) So plus the top half, which is 8/16, you get 9/16.
Answers: left picture: 3/16.
right picture: 9/16.