2+ a + b = a + 2 + b is an example of which algebraic property? (5 point)

distributive property
associative property of addition
commutative property of addition
symmetric property

Researchers were interested in whether relaxation training decreases the number of headaches a person experiences. they randomly assigned 20 participants to a control group or a relaxation training group and noted the change in number of headaches each group reported from the week before training to the week after training. which statistical analysis should be performed to answer the researchers' question?

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

Given the equation −4  = 12, solve for x and identify if it is an extraneous solution.