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(x+1)•(x+3)=12. x=? pls

Răspuns :

Lacramioara9cl
x^2+3x+x+3-12=0
x^2+4x-9=0
a=1.
b=4
c= -9. delta = b^2-4ac=4^2-4*1*(-9)=16+36=52
x1=-b-√delta/2a=-4-√52/2*1=-4-2√13/2=-2-2√13
x2=-b+√delta/2a=-4+√52/2*1=-4+2√13/2=-2+2√13
x²+3x+x+3=12
x²+4x+3-12=0
x²+4x-9=0
a=1
b=4
c=-9
Δ=b²-4ac=4²-4·1·(-9)=16+36=52
x1=(-b+√Δ)/2a=(-4+Δ52)/2·1=(-4+2√13)/2=2(-2+√13)/2=-2+√13
x2=(-b-√Δ)/2a=(-4-Δ52)/2=2(-2-√13)/2=-2-√13
S={-2-√13, -2+√13)

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