a) (2x+4)(x+2)=0
2x(x+2) +4(x+2)=0
2x²+4+4x+8=0
2x²+4x+ 8=0
Δ=b²-4ac= 4² - 4*2*8= 16 - 64 = -48 ⇒ S ∈ multimii vide
f) (x-3)²=0
x² - 6x + 9=0
Δ=b² - 4ac= -6² - 4*1*9= 36 -36= 0 ⇒ x= -b/2a = 6/2 = 3
g) -2(3x+5)²=0
-2(9x²+30x+25)=0
-18x²-60x-50=0
Δ=b²-4ac= -60²-4*(-18)*(-50)= 3600 -3600=0 ⇒x= -b/2a = 60/-36= 10/-6 = 5/-3
