Réponse :
pour x = 5
4x + 8
= 4 × 5 + 8
= 20 + 8
= 28
7 - 3x
= 7 - 3 × 5
= 7 - 15
= -8
4 + x³
= 4 + 5³
= 4 + 5 × 5 × 5
= 4 + 125
= 129
x² - 10
= 5² - 10
= 5 × 5 - 10
= 25 - 10
= 15
pour x = -4
4x + 8
= 4 × 4 + 8
= 16 + 8
= 24
7 - 3x
= 7 - 3 × 4
= 7 - 12
= -5
4 + x³
= 4 + 4³
= 4 + 4 × 4 × 4
= 4 + 64
= 68
x² - 10
= 4² - 10
= 4 × 4 - 10
= 16 - 10
= 6