When something says 'solve for the system of equations' they are looking for a point where the graph of the two functions intersects. Since they give you the graph, the two functions approximately intersect somewhere between the x-value of -6 and -7 (i.e. -6.5) and somewhere between the y-value of -3 and -4 (i.e. -3.5). So, the closest estimate is (-6.5, -3.5) or A.
If the perimeter is 39 what you have to do is 39 - 8.5 - 8.5 that will give you 22 and divide 22/2 and that gives you 11. So 11 is the length
A tessellation is the regular t<span>iling of a plane shape</span>
The missing justification is for the statement that three angles add to a particular angle. The appropriate choice is ...
... c. Angle Addition Postulate
