Answer:
49x^4-70x^3+319x^2-420x+150, first option
Step-by-step explanation:
Just do (7x^3-5x^2+42x-30) times (7x-5)
and you will get 49x^4-35x^3-35x^3+25x^2+294x^2-210x-210x+150.
All this would simplify to the first option.
49x^4 - 35x^3 - 35x^3 + 25x^2 + 294x^2 - 210x - 210x + 150
= 49x^4 - 70x^3 + 319x^2 - 420x + 150
ANSwer: The first one.
