Bonjour ;
Exercice n° 1 .
Voit la figure ci-jointe .
Exercice n° 2 .
A = - (2x - 3x² + 5y) - (y² + 2x)
= - 2x + 3x² - 5y - y² -2x
= 3x² - 4x - y² - 5y .
B = - (4x - 3y + 3) - (3x + 4z) - (4x - 3y + 4z)
= - 4x + 3y - 3 - 3x - 4z - 4x + 3y - 4z
= - 11x + 3y - 8z - 3 .
C = - (4x - 5x² + 3y - 4y²) + 2 - 4x² + (2x² - 3) - 4(x - x² - y²)
= - 4x + 5x² - 3y + 4y² + 2 - 4x² + 2x² - 3 - 4x + 4x² + 4y²
= 7x² - 8x + 8y² - 3y - 1 .
Exercice n° 3 .
A = 4x - 4 = 4(x - 1) .
B = 3x² + 2x = x(3x + 2) .
C = (3 - x)(2 + 4x) - (3 - x)
= (3 - x)(2 + 4x - 1)
= (3 - x)(1 + 4x) .
D = (4x - 5)(1 + 2x) - (1 + 2x)²
= (4x - 5)(1 + 2x) - (1 + 2x)(1 + 2x)
= (1 + 2x)(4x - 5 - 1 - 2x)
= (1 + 2x)(2x - 6)
= 2(1 + 2x)(x - 3) .
