What dose the underlined 8 round to in 8,842 -

What are the solutions of the equation? 5z^2 + 9z - 2 = 0 a. 1, -2 b. 1, 2 c. 1/5, -2 d. 1/5, 2

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?

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.