Which exspression is equivalent to 6a - 12a + 13b Ik the answer but my teacher telling me I’m wrong so what answer do you think it is

How do i do this using elimination 2x+3y=12 x-y=6

G(x) = 2 sin(2x - π) + 4. using complete sentences, explain how to find the minimum value for the function.

Use the ratio test to determine whether ∑n=14∞n+2n! converges or diverges. (a) find the ratio of successive terms. write your answer as a fully simplified fraction. for n≥14, limn→∞∣∣∣an+1an∣∣∣=limn→∞.