can you please explain how to get these solutions

Problem 4 (6 points, 2 pt each): State whether each of these functions is a bijection from R to R. (R is the set of real numbers.) Remember, a bijection is a function that is one-to-one and onto. a) f(x)-2x+1 SOLUTION: Yes, because it is one-to-one and onto. b) f(x)-2+1 SOLUTION: No, because it is neither one-to-one nor onto. SOLUTION: Yes, because it is one-to-one and onto