bonsoir
c. x² + 2x + 1 = 0
( x + 1 )² = 0
x = - 1
e. 7x² - 14 = 0
7 ( x² - 2 ) = 0
x² - 2 = 0
x² = 2
x = √ 2 ou - √2
b. 4x² + 7 = 0
4 x² = - 7
pas de solution dans R
d. 2x² = x
2 x² - x = 0
x ( 2 x - 1 ) = 0
x = 0 ou 1 /2
f. 2(5x + 7)(-3x + 2) = 0
x = - 7/5 ou 2/3