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h) (2x+1)(-5x+2)/(3x+7) ≦ 0
tableau de signes
x      -inf           -7/3           -1/2             2/5             +inf
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2x+1         -                -        0         +            +           
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-5x+2         +             +                  +     0        -
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3x+7          -       0      +                +                 +
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f(x)            +       ||      -         0       +      0         -
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donc S=]-7/3;-1/2] U [2/5;+inf[

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