Bonjour
1)
A = 2 (5 + x) - 7 (5x - 8)
A = 10 + 2x - 35x + 56
A = - 33x+ 66
B = 1/11 (7x - 5) - 1/3 (x + 2)
B = 7/11x - 5/11 - 1/3x - 2/3
B = 21/33x - 11/33x - 15/33 - 22/33
B = 10x/33 - 37/33
C = 27 (x - 2) - (10x - 20) (x - 1)
C = 27x - 54 - (10x² - 10x - 20x + 20)
C = 27x - 54 - 10x² + 10x + 20x - 20
C = - 10x² + 57x - 74
2)
A * B
= (- 33x + 66) * (10x/33 - 37/33)
= - 330x²/33 + 1 221x/33 + 660x/33 - 2 442/33
= - 10x² + 1881x/33 - 74
= - 10x² - 57x - 74.
