Please say whether they are equivalent or not

Find the cosine function that is represented in the graph.

Sandy is ordering bread rolls for her party,she wants 3/5 of the rolls to be whole wheat. what other factions can represent part of the rolls that will be whole wheat? shade the models to show your work.

Two times a number plus three times another number equals 4. three times the first number plus four times the other number is 7. find the numbers