Find the cosine . Write as decimal rounded to the nearest tenth

Select all the correct answers. what is 221,000,000,000,000,000,000 expressed in scientific notation?

What is the value of the discriminant of the quadratic equation -2x = -8x + 8 and what does its value mean about thenumber of real number solutions the equation has?

Matt had 5 library books. he checked out 1 additional book every week without retuening any books. whats the matching equation