Is the set of multiples of 4 closed under addition? explain why or provide a counterexample if not.

a. yes, because the sum of any two multiples of 4 is also a multiple of 4.

b. yes, because the sum of any two multiples of 4 is also a multiple of 8.

c. no, and a counterexample is –4 + (–8) = –12.

d. no, and a counterexample is 26 + 16 = 42.

20 points 1. your friend, taylor, missed class today and needs some identifying solutions to systems. explain to taylor how to find the solution(s) of any system using its graph. 2. taylor graphs the system below on her graphing calculator and decides that f(x)=g(x) at x=0, x=1, and x=3. provide taylor some feedback that explains which part of her answer is incorrect and why it is incorrect. f(x)=2x+1 g(x)=2x^2+1