Here's link to the answer:

To find the perfect square needed, you take the "middle" value and half it, then square it. so in this case, take -6, half it into 3, and square it to get 9. you'll be adding 9 to both sides
Let's try the actual solution of the system
<span>y = –2x + 1
y = –2x – 3
Note that the slopes of the graphs of these two lines are the same: -2.
That means that the lines are parallel to one another.
Only the y-intercepts (1 and -3) are different.
Since the 2 lines never intersect, the system has no solution.
</span>
Sum of all exterior angle should be 360.
when the measure of each exterior angle is 36 then it has 10 sides and it is a
<span>Decagon </span>