What are the two main ways in which chemical bonds are formed

At very high pressures, gases become and will eventually a) more dense; become hotter b) more dense; change to a liquid or solid c) less dense; combust d) less dense; turn into a liquid

What is the magnitude of the acceleration vector which causes a particle to move from velocity −5i−2j m/s to −6i+ 7j m/s in 8 seconds. answer in m/s.

Aria drove to the store, did some shopping, and then came home. during maria's trip, when was her displacement equal to zero?