Question

4-A solução da inequação x² + 2x ≤ 35 é:
(A)S = { x ∈ R/ 9< x > 5 }
(B) S = { x ∈ R/ x >5 }
(C) S = { x ∈ R / 7 < x > 8 }
(D) S = { x ∈ R / -7 < x > 5 }



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Answer 1

Resposta:

ITEM (D)

Explicação passo-a-passo:

${x}^{2} +2x \leqslant 35$

${x}^{2} + 2x - 35 \leqslant 0$

${x}^{2} + 7x - 5x - 35 \leqslant 0$

$x \times (x + 7) - 5(x + 7) \leqslant 0$

$(x + 7) \times (x - 5) \leqslant 0$

$\left \{ {{x + 7 \leqslant 0} \atop {x - 5 \geqslant 0}} \right. \\ \left \{ {{x + 7 \geqslant 0} \atop {x - 5 \leqslant 0}} \right.$

$\left \{ {{x \leqslant - 7} \atop {x \geqslant 5}} \right. \\ \left \{ {{x \geqslant - 7} \atop {x \leqslant 5}} \right.$

$x∈Ø \\ x∈[ - 7,5]$

$\red{x∈[ - 7,5]}$