What is the purpose of checks and balances and separation of powers in the constitution

Checks and balances: the system ensures that all of the branches maintain equal power by giving each of them a check against one another.
(System gives each of the three branches of government ways to limit the powers of the other branches)
Separation of powers: idea that the government should be divided into 3 distinct and separate branches, such as the legislative branch, executive branch and the judicial branch.
(Constitutional authority is shared by three different branches of government)