For the ARMA(2,1) process yt=2/5y(t-1)-4/5y(t-2)-et+4/5(t-1) where en WN(0,sigma). What is the absolute value of the second root of the AR characteristic equation.​

Pick the expression that matches this description: a polynomial of the 5th degree with a leading coefficient of 7 and a constant term of 6 (choice a) 7x^5+2x^2+6 (choice b) 7x^6−6x^4+5 (choice c) 6x^7−x^5+5 (choice d) 6x^5+x^4+7

Marina baked cookies. she gave 3/4 of the cookies to the scout bake sale. she shared the remaining 6 cookies with her friends. how many cookies did marina bake?

If your teacher tells you to do questions 6 through 19 in your math book for homework, how many questions is that