Sagot :
Bonjour,
1)
(x-6)² - (x-6) ( 2x-5) = x² - 12x + 36 -( 2x² - 5x - 12x + 30)
= x² - 12x + 36 - 2x² + 5x + 12x - 30
= -x² + 5x + 6
2)
(x-6)² - (x-6) ( 2x-5) = (x-6) (x - 6 - 2x + 5)
= (x-6) (-x -1)
= (6-x) (x+1)
3)a)
9t² - 27t = 9t * t + 3 * 9t = 9t (t+3)
b)
-3z + 15 = 15 - 3z = 3*5 - 3z = 3( 5-z)
Bonjour,
1. Développer :
A = (x - 6)² - (x - 6)(2x - 5)
>> identité remarquable :
- (a - b)² = a² - 2ab + b²
A = x² - 12x + 36 - (x - 6)(2x - 5)
>> double distributivité :
- (a + b)(c + d) = ac + ad + bc + bd
A = x² - 12x + 36 - (2x² - 5x - 12x + 30)
A = x² - 12x + 36 - (2x² - 17x + 30)
A = x² - 12x + 36 - 2x² + 17x - 30
A = -x² + 5x + 6
✅
2. Factoriser au maximum :
A = (x - 6)² - (x - 6)(2x - 5)
A = (x - 6)(x - 6) - (x - 6)(2x - 5)
A = (x - 6)(x - 6 - (2x - 5))
A = (x - 6)(x - 6 - 2x + 5)
A = (x - 6)(-x - 1)
A = -(x - 6)(x + 1)
A = (-x + 6)(x + 1)
A = (6 - x)(x + 1)
✅
B = 9t² - 27t
B = 9t * t - 9t*3
B = 9t(t - 3)
✅
C = -3z + 15
C = 3 * (-z) + 3 * 5
C = 3(5 - z)
✅
* = multiplication
Bonne journée