Répondre :
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[
tableau de signes
x -inf -7/3 -1/2 2/5 +inf
----------------------------------------------------------------------------------
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[