Question in the attachment below

Can someone answer this question? : )

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

Add the fractions, and simply the result to lowest terms. 2/3 + 2/7= ?