If cosx+sinx=sqrt(2)cosx then show that cosx-sinx=sqrt(2)sinx

Brian, chris, and damien took a math test that had 20 questions. the number of questions brian got right is 14 more than the number of questions chris got right. damien correctly answered 2 less than the number of questions chris answered correctly. if brian and damien have the same score, which statement is true?

Alana has 12.5 cups of flour with which she is baking four loaves of raisin bread and one large pretzel. the pretzel requires 2.5 cups of flour to make. how much flour is in each loaf of raisin bread? explain the steps to follow to get the answer.

Weekly wages at a certain factory are normally distributed with a mean of $400 and a standard deviation of $50. find the probability that a worker selected at random makes between $450 and $500