Sagot :
bonjour
C = - 18 - x + 9 + 8 + x
= - 1
d = x² + 6 x - 4 - 5 x + x² + 4
= 2 x² + x
E = 3 y² - 2 y + 7 + y² - 5 y + 6
= 4 y² - 7 y + 13
bonjour
C = -18-(x-9)-(-8-x)
= -18 - x + 9 + 8 + x
= -18 + 9 + 8
= -9 + 8
= -1
D = (x²+6x-4)-(5x-x²-4)
= x² + 6 x - 4 - 5x + x² + 4
= 2x² + x
E= 3y²-(2y-7)-(y²+5y-6)
= 3y² - 2y + 7 - y² - 5y + 6
= 2y² -7y + 13
bonne journée