Respuesta :

Answer:I think the answer is 6x because

18= 6x3

42= 6x7

30= 6x5

Step-by-step explanation:

18= 6x3

42= 6x7

30= 6x5 And 6x(3x+7x^3+5x^4) it became 18x^2+42x^4+30x^5