What does it mean to express y in terms of x?

When an equation expresses y, it is basically saying something like this: "y = ". When an equation expresses y in terms of x, the blank space is filled with numbers based on x. For example, expressing y in terms of x could be "y = 2x". This would mean that y is equal to whatever x is times 2. 

Top right since it passes vertical line test

You have 2 sides that are 2 cms and you have 6 sides that are 1/2 cm and you have 4 sides that are 1 cm. the smallest sides are 1/2 the medium sized sides are 1 and the smallest are 1/2. so to find the perimeter you have to add them all up together so your answer will be 11 cm's