Solve the system of equations 2x+7y=-5 and-x-6y=10

Find the value of tan theta if sin theta = 12/13 and theta is in quadrant 2

In the figure below, ∠dec ≅ ∠dce, ∠b ≅ ∠f, and segment df is congruent to segment bd. point c is the point of intersection between segment ag and segment bd, while point e is the point of intersection between segment ag and segment df. the figure shows a polygon comprised of three triangles, abc, dec, and gfe. prove δabc ≅ δgfe.

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