Question

Rezolvati in R inecuatiile:a)x²+3x+2>0 ,b)(x-3)(x+7)≥0

Answer 1

[tex]x^2+3x+2\ \textgreater \ 0 a=1 b=3 c=2 delta = b^{2}-4ac = 3^2-4*1*2=9-8=1 x_{1}= \frac{-3+1}{2}= \frac{-2}{2}=-1 x_{2}= \frac{-3-1}{2}= \frac{-4}{2}=-2 [/tex]

[tex]x^2+7x-3x-21=0 x^2+4x-21=0 a=1 b=4 c=-21 delta= b^{2} -4ac= 4^2-4*1*(-21)= 16+84=100 x_{1}= \frac{-4+10}{2}= \frac{6}{2}=3 x_{2}= \frac{-4-10}{2}= \frac{-14}{2}=-7 [/tex]

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