Answered

Bonjour, j'ai vraiment beaucoup de difficulté avec mon devoirs de maths... Pouvez m'aider?
Il faut les factoriser
a= (2a - 1)(a - 5) + (a + 1)(a - 5) = ?
b= (3a + 7)( 2a - 9) - (3a + 7)^2 = ?
c = a(2a + 1) - (2a + 1) =? d = 49a^2 + 56a + 16 =?
e = 25a^2 - 30a + 9 = ?
f = 25 - 9a^2 = ?
mercii !

Sagot :

FAMILYS

Bonsoir,

a = (2a - 1)(a- 5) + (a + 1)(a - 5)

a = (a - 5)[(2a - 1) + (a + 1)]

a = (a - 5)(2a - 1 + a + 1)

a = (a - 5)(3a)

b = (3a + 7)( 2a - 9) - (3a + 7)²

b = (3a + 7)(2a - 9) - (3a + 7)(3a + 7)

b = (3a + 7)[(2a - 9) - (3a + 7)]

b = (3a + 7)(2a - 9 - 3a - 7)

b = (3a + 7)(-a - 16)

c = (a)(2a + 1) - (1)(2a + 1)

c = (2a + 1)(a - 1)

d = 49a² + 56a + 16

d = (7a + 4)²

e = 25a² - 30a + 9

e = (5a - 3)²

f = 25 - 9a²

f = 5² - (3a)²

f = (5 + 3a)(5 - 3a)