Bonsoir;
x²(x-3)-9(x-1)²(x-3)
= x³ -3x² -9( x² -2x+9) ( x-3)
= x ³ -3x² - (9x² +18x -81)( x-3)
= x³ -3x² -9x³ +18x² -81x +27x² - 54x - 243
= - 8x³ +41x² - 135x -243
