Which of the following systems of linear inequalities is represented by the solution graphed below?

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

Money off coupons have been circulated to 300 households. only 2/5 of these were redeemed (used) in the local supermarket to get a free shampoo. what fraction of coupons were unused? (ps: write how you got the answer)

Which best explains why this triangle is or is not a right triangle ?