800+150? please tell me

What is the simplified form of square root of 400 to the 100th power ?

Vertical angles must check all that apply

How do you find p(a and b) if a and b are independent events for two or more actions, such as tossing a coin twice and finding p(heads and heads)? 2. how do you find p(a or b) if a and b are independent events for one action, such as spinning a four-color spinner once and finding p(red or blue)?