Explications étape par étape:

1)P = (2x)² - (2×2x×3) + 3² - (10x² -2x - 15x + 3)

= 4x² - 12x + 9 - 10x² + 17x -3

= -6x² + 5x + 6

2) P =(2x-3)(2x-3 - 5x + 1)

P = (2x -3)(-3x - 2)

3)

P = [(2×-10) -3]² - [(2×-10)- 3][(5×-10)-1]

= (-20-3)² - (-20-3)(-50-1)

= (-23)² - (-23)×(-51)

= 529 - 1 173

= -644

P = -6 × (-10)² + 5×(-10) + 6

P = -6×100 + (-50) + 6

P =.-600 - 50 + 6

P = -650 + 6

p = -644

p = [(2×-10) - 3][(-3×(-10)) - 2]

P = (-20-3) ( 30 - 2)

P =.-23 × 28

P = -644