How do i simplify 12[309]

Can any one me with the answers to these questions asap?

Sum of the interior angles of a pentagon

1) your friend taylor missed class today and needs some identifying solutions of systems. explain to taylor where to find the solution(s) of any system using its graph 2)taylor graphs the following in desmos and decides that f(x) = g(x) at x = 0, x = 1, & x = 3. f(x) = 2x+1g(x) = 2x2+1 provide taylor some feedback that explains which part of the answer was incorrect and why.