When you have to describe a 3D shape you have to keep the following definitions in mind:
<em>1. The face of a 3D shape is a flat surface.</em>
The shape on the picture has 3 rectangular faces and 2 triangular faces, a total of 5 faces.
<em />
<em>2. The edge is where two faces meet.</em>
For the shape on the picture, there are 3 edges, where the rectangular faces meet each other, and then three edges where the rectangular faces meet each of the triangular faces, this shape has a total of 9 edges.
<em>3. The vertex is a corner, where the edges meet.</em>
There are three vertices on each end of the shape, so it has a total of 6 vertices.
A shape that has 5 faces, 9 edges, and 6 vertices is a triangular prism.
Attached a solution and showed work.
Answer: This is true because everything in the first equation was multiplied equally to get to the second equation. Every part was multiplied by three. The first equation is x-7=3 and the second can be seen as 3(x-7=3). The three will not affect x seeing that the entire equation had the same thing done to it.
