Bonsoir,
1. A = (x - 3y) - (x + 2z)
A = x - 3y - x - 2z
A = -3y - 2z
2. A = (1,2 - 3(-1) ) - (1,2 + 2(-1,5) )
A = (1,2 + 3 ) - (1,2 - 3 )
A = (4,2) - (-1,8)
A = 4,2 + 1,8
A = 6
3. B = 0² - 3(0) + 1
B = 1
B = 1² - 3(1) + 1
B = 1 - 3 + 1
B = -2 + 1
B = -1