Răspunsuri

2014-10-13T16:20:37+03:00
1) ax²+bx+c=0
x²+5x-4x-20=11
x²+x-20-11=0
x²+x-31=0
Δ=b²-4ac
Δ=1²-4*1*31
Δ=125
x₁= (-b+√Δ)/2a
x₁=(-1+15)/2 =14/2=7
x₂= (-b-√Δ)/2a
x₂=(-1-15)/2=-16/2=-8 
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