Bonjour,
1)
a. 4x² + 4 = 4 (x² + 1)
b. 8 - 2a = 2 (4 - a)
c. 5xy - 10x = 5x (y - 2)
2)
a.
A = - 7(x - 2)
A = - 7x + 14
B = (4x + 5) (x + 3)
B = 4x² + 12x + 5x + 15
B = 4x² + 17x + 15
C = (9 + x) (3x - 1)
C = 27x - 9 + 3x² - x
C = 3x² + 27x - x - 9
C = 3x² + 26x - 9
D = (6x - 2) (5x - 3)
D = 30x² - 18x - 10x + 6
D = 30x² - 28x + 6
b. Pour x = 1
A = - 7x + 14
A = - 7 * 1 + 14
A = - 7 + 14
A = 7
B = 4x² + 17x + 15
B = 4 * (1)² + 17 * 1 + 15
B = 4 + 17 + 15
B = 36
C = 3x² + 26x - 9
C = 3 * (1)² + 26 * 1 - 9
C = 3 + 26 - 9
C = 29 - 9
C = 20
D = 30x² - 28x + 6
D = 30 * (1)² - 28 * 1 + 6
D = 30 - 28 + 6
D = 36 - 28
D = 8
3)
B - C = 36 - 20 = 16
4)
A - B + C - D = 7 - 36 + 20 - 8 = 27 - 44 = - 17
