a²+2 = 8-a

(-5)²+2 =8-(-5)

25+2 =8+5

27 = 13

faux

a²+2 =8-a

(-3)²+2 =8-(-3)

9+2 = 8+3

11 =11

vraie

a²+2 = 8-a

2²+2 = 8-2

4+2 = 6

6 = 6

vraie

a²+2 =8-a

8²+2 = 8-8

64+2 =0

66 =0

donc faux