1.5(a -4) - 2 = 4 pls help ASAP and show checked answer

On an airplane there are two seats on the left side and three seats on the right side there are 90 seats o the right side of the plane

Which of these equations, when solved, gives a different value of x than the other three? a9.1 = -0.2x + 10 b10 = 9.1 + 0.2x c10 – 0.2x = 9.1 d9.1 – 10 = 0.2x

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