Sagot :
Bonsoir,
A= (2x-1) (7x+15)
= 14x² +30x - 7x - 15
= 14x² +23x -15
B= (3x+7) (9x+2)
= 27x² +6x +63x +14
= 27x² +69x +14
C = (6x-4) (8x-3)
= 48x² -18x -24x +12
= 48x² -42x +12
Bonsoir,
Réaliser ces différents calculs :
A = (2x - 1)(7x + 15)
>> double distributivité :
- (a + b)(c + d) = ac + ad + bc + bd
A = 2x * 7x + 2x * 15 - 7x - 15
A = 14x² + 2x * 15 - 7x - 15
A = 14x² + 30x - 7x - 15
A = 14x² + 23x - 15
B = (3x + 7)(9x + 2)
>> double distributivité :
- (a + b)(c + d) = ac + ad + bc + bd
B = 3x * 9x + 3x * 2 + 7 * 9x + 7 * 2
B = 27x² + 3x * 2 + 7 * 9x + 7 * 2
B = 27x² + 6x + 7 * 9x + 7 * 2
B = 27x² + 6x + 63x + 7 * 2
B = 27x² + 6x + 63x + 14
B = 27x² + 69x + 14
C = (6x - 4)(8x - 3)
>> double distributivité :
- (a + b)(c + d) = ac + ad + bc + bd
C = 6x * 8x - 6x * 3 - 4 * 8x - 4 * (-3)
C = 48x² - 6x * 3 - 4 * 8x - 4 * (-3)
C = 48x² - 18x - 4 * 8x - 4 * (-3)
C = 48x² - 18x - 32x - 4 * (-3)
C = 48x² - 18x - 32x + 12
C = 48x² - 50x + 12
* = multiplication
Bonne soirée.