Answer:
Step-by-step explanation:
Answer:I think the answer is 6x because
18= 6x3
42= 6x7
30= 6x5
30= 6x5 And 6x(3x+7x^3+5x^4) it became 18x^2+42x^4+30x^5
180 - x = r is true.
Thats the only one which is true.