How many layers of the earth are they

there are 3 layers.

The Earth has Three Layers

Inner Core, Outer Core, Mantle, Upper Mantle, and Crust

Explanation:

​​The earth is made up of three different layers: the crust, the mantle and the core. This is the outside layer of the earth and is made of solid rock, mostly basalt and granite. There are two types of crust; oceanic and continental.

reflecting point a across the origin negates both of its coordinates.

b = (5, -4)