Step-by-step explanation:

Answer:mkay, also yes he did
Step-by-step explanation:
1.Remove the parentheses
2.put -5z and 4z together which makes -9z(negative plus positive equals negative)
3.-9z+ -6z=-3z and 7+8=15
4.15 decided by -3=5
so yes, z=-5
Perimeter is a measure of the area or distance around a two-dimensional shape. On a rectangle, for instance, the perimeter is the total length of the rectangle's outline, including the two widthwise borders and the two lengthwise borders.
<u><em> To determine the perimeter of a shape</em></u>, therefore, you add together all the dimensions that make up the shape's outer edge. Being able to find the perimeter of a shape has many applications in the real world. Say, for example, that you wanted to build a fence around your backyard. In order to purchase materials, you need to know how much fencing you'll need, and to determine that you have to figure out the perimeter of the area you want to fence in.
Answer:
Step-by-step explanation:
The different isotopes have different "half-lives" – the time it takes to lose half of its radioactivity. Pu-239 has a half-life of 24,100 years and Pu-241's half-life is 14.4 years. Substances with shorter half-lives decay more quickly than those with longer half-lives, so they emit more energetic radioactivity.