Răspuns :
4x^2 - 12x + 9 - 81 = 0
(2x-3)^2 - 9^2 = 0
(2x-3-9)(2x-3+9)=0
(2x-12)(2x+6)=0
4(x-6)(x+3)=0
sol.(6, -3)
4x²-12x+9-81=0
4x²-12x-72=0
Δ=b²-4ac= 144+1152=1296
x1=(b1-√Δ)/2a=(12+36)/8=48/8=6
x2=(12-36)/8= -24/8 = -3
4x^2 - 12x + 9 - 81 = 0
(2x-3)^2 - 9^2 = 0
(2x-3-9)(2x-3+9)=0
(2x-12)(2x+6)=0
4(x-6)(x+3)=0
sol.(6, -3)
4x²-12x+9-81=0
4x²-12x-72=0
Δ=b²-4ac= 144+1152=1296
x1=(b1-√Δ)/2a=(12+36)/8=48/8=6
x2=(12-36)/8= -24/8 = -3