Answer:
A - [tex]3x - 4[/tex]
Step-by-step explanation:
A polynomial written in the standard form should be written in the form of decreasing or descending powers. Since [tex]3x[/tex] has a higher power than 4 i.e. [tex]3x = 3x^{1}[/tex] and [tex]4 = 4x^{0}[/tex], 1 is higher than 0, thus option A.
In option C, [tex]2x[/tex] has a higher power than 5, but 5 is put before [tex]2x[/tex], so it can't be correct.
