What is the unit rate of $120 15 books

What is the explicit formula for this sequence? -7, -4, -1, 2, a.) an = 8 + (b - 1)3 b.) an = -7 + (n - 1)3 c.) an = 3 + (n -1) (-7) d.) an = -7 + (n - )

Given: klmn is a parallelogram m? n=3m? k, lf ? kn , ld ? nm kf=2 cm, fn=4 cm find: lf, ld

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