Think about the prefix co-
cooperation
cosign
co-president
It's typically used to describe things that are <em>shared</em> or <em>mutual</em>. We say that two points are <em>coplanar</em> when they <em>share the same plane.</em>
I think the perimeter is 11x-1y+7, after combining like terms. Not sure about the area though.
1. 31e+16
hope that helps
The first one. The sum of all angles on a triangle is always equal to 180
