Sagot :
2x^2-4(2x+6) avec x=4:
2*(4^2)-4(2*4+6)
= -24
2)
2x^2-4(2x+6)=2(x+2)(x-6)=2x^2-8x-24
3)
2x^2-4(2x+6)=2x^2-4x+1
-8x-24= -4x+1
-8x+4x=24+1
-4x=25
x= -25/4
2*(4^2)-4(2*4+6)
= -24
2)
2x^2-4(2x+6)=2(x+2)(x-6)=2x^2-8x-24
3)
2x^2-4(2x+6)=2x^2-4x+1
-8x-24= -4x+1
-8x+4x=24+1
-4x=25
x= -25/4
Bonsoir,
a) calculons 2x² - 4(2x + 6) pour x = 4
• 2 × 4² - 4(2 × 4 + 6)
= 2 × 16 - 4(8 + 6)
= 32 - 4 × 14 = 32 - 56
= -24 ✅
b) 2x² - 4(2x + 6)
= 2x² - 4 × 2x - 4 × 6
= 2x² - 8x - 24 ✅
c) 2x² - 4(2x + 6) = 2x² - 4x + 1
• 2x² - 8x - 24 = 2x² - 4x + 1
• 2x² - 2x² -8x + 4x = 1 + 24
• -4x = 25
• x = -25/4 ✅
Bonne soirée !