Greetings from Brasil...
A 1st degree function can be written in two ways:
F(X) = AX + B
or
Y = AX + B
note that F(X) = Y
So, looking at the alternatives in the question, only Y = 7X/3 - 8 is equivalent to Y = AX + B, where:
A = 7/3
B = - 8
then
a function of the 1st degree
answer:
Y = (7/3)X - 8