Answer :
Step-by-step explanation:
f (x) - g (x) = 9 x³ + 2 x² - 5 x + 4 - ( 5 x³ - 7 x + 4 ) =
9 x³ + 2 x² - 5 x + 4 - 5 x³ + 7 x - 4 =
9 x³ - 5 x³ + 2 x² - 5 x + 7 x + 4 - 4 =
4 x³ + 2 x² + 2 x =
2 x ∙ ( 2 x² + x + 1 )
- 9x³+2x²-5x+4-(5x³-7x+4)
- 9x³+2x²-5x+4-5x³+7x-4
- 9x³-5x³+2x²-5x+7x+4-4
- 4x³+2x²+2x
- 2x(2x²+x+1)