28.2k views
1 vote
J’ai besoin d’aide pour cet exercice

J’ai besoin d’aide pour cet exercice-example-1
User Cannin
by
3.0k points

1 Answer

6 votes

Answer:

Explanation:

A(x) = 4x³ - 4x²- 23x + 20

B(x) = 2x² + 3x - 4

C(x) = 2x - 5

a). A(x) + B(x) + C(x) = (4x³ - 4x²- 23x + 20) + (2x² + 3x - 4) + (2x - 5)

= 4x³ + (-4x² + 2x²) + (-23x + 3x + 2x) + (20 - 4 - 5)

= 4x³- 2x²- 18x + 11

b). A(x) - 2B(x) + 2C(x) = (4x³ - 4x²- 23x + 20) - 3(2x² + 3x - 4) + 2(2x - 5)

= 4x³ - 4x² - 23x + 20 - 6x² - 9x + 12 + 4x - 10

= 4x³ - 10x²- 28x + 22

c). A(x) . B(x) = (4x³ - 4x² - 23x + 20)(2x² + 3x - 4)

= 2x²(4x³ - 4x² - 23x + 20) + 3x(4x³ - 4x² - 23x + 20) - 4(4x³ - 4x² - 23x + 20)

= 8x⁵ - 8x⁴- 46x³ + 40x² + 12x⁴- 12x³ - 69x² + 60x - 16x³+ 16x²+ 92x - 80

= 8x⁵+ 4x⁴- 74x³- 13x²+ 152x - 80

d). [B(x)]² = (2x² + 3x - 4)²

= 2x²(2x² + 3x - 4) + 3x(2x² + 3x - 4) - 4(2x² + 3x - 4)

= 4x⁴ + 6x³ - 8x² + 6x³ + 9x² - 12x - 8x² - 12x + 16

= 4x⁴ + 12x³- 7x²- 24x + 16

User Kadrian
by
3.5k points