In these kind of problems, it's always the best to just draw it. There are "formulas" to calculate this, but it's better to know intuitively.
Midpoint, as the name suggests is the point that is exactly halfway between two points. To find a midpoint in one dimension, we would take an average between those two points.
Example: Number exactly halfway between 8 and 16 is

We can do the same for two dimensions, it just means we'll have to calculate both for x-values and y-values
Midpoint
Answer:
i think its y = x² + 6x - 55
It is 55:11. What number can both those numbers divide by? 11.
55/11=5
11/11=1
So the answer is 5:1.
y-2 = 38
parallel side have the same length in a parallelogram
add 2 to each side
y =40
17 = x+3
parallel side have the same length in a parallelogram
subtract 3 from each side
14 =x
opposite angles are equal in a parallelogram
124 = 2u
divide by 2
u = 63
angles on the same side add to 180
124+ v-3 =180
121+v=180
v = 59