hello !
1.
A = a + b + ab
= 2 + 5 + (2 × 5)
= 2 + 5 + 10
= 17
B = 2a - 3b
= [2 × (-1)] - (3 × 3)
= -2 - 9
= -11
C = a² + 2ab
= -2² + [2 × (-2) × (-3)]
= 4 + 12
= 16
2.
A = a² + 2ab + b²
= x² + 2x × 1 + 1²
= x² + 2x + 1
B = a² - 2ab + b²
= 2x² - (2 × 2x × 3) + 3²
= 2x² - 12x + 9
C = a² - b²
= -2² - x²
= 4 - x²
En espérant t'avoir aidé(e) ! ^^
