Plz i’m very dumb and cannot do this

An angle that measures between 90 and 180° is called a(,

To solve the system of equations below, grace isolated the variable y in the first equation and then substituted into the second equation. what was the resulting equation? 3y=12x x^2/4+y^2/9=1

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