What is similar about why congress and the courts informally change the constitution? how do their methods changing the constitution vary?

Informal methods are used more than formal because formally amending the constitution requires achieving the popular vote,which is difficult task to achieve.

Once the bill has passed both houses,it goes to the states.

The other method is for the Constitutional Convention to be called by two-thirds of the legislatures of the states,and for that Convention to propose one or more amendments.

silk

indigo  

rice

all the other answers are wrong