Bonsoir
(x-3)² - 25 = 0
Identité remarquable
a² - b² = ( a+b)(a-b)
(x-3-5)(x-3+5) = 0
( x - 8 ) ( x + 2 ) = 0
x = 8 ou x = - 2
S = { 8;-2 }
(2x-4)² -9x² = 0
( 2x-4-3x)(2x-4+3x) = 0
( -x - 4 ) ( 5x - 4 ) = 0
-x = 4 ou 5x = 4
x = -4 ou x = 4/5
S = {-4;4/5}
Bonne soirée et bonnes vacances
Bonjour,
(x-3)² - 25 = 0
(x - 3)² - 5² = 0
(x - 3 - 5)(x - 3 + 5) = 0
(x - 8)(x + 2) = 0
x - 8 = 0 ou x + 2 = 0
x = 8 ou x = -2
(2x-4)² - 9x² = 0
(2x - 4)² - (3x)² = 0
(2x + 3x - 4)(2x - 3x - 4) = 0
(5x - 4)(-x - 4) = 0
5x - 4 = 0 ou -x - 4 = 0
5x = 4 ou x = -4
x = 4/5 ou x = -4