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Rezolvati in R sistemul de inecuatii:
{3-4x>5
{6+9x<=1


Răspuns :

[tex] 3-4x>5 => -4x>2 => x< \frac{2}{-4} <=> x< -\frac{1}{2} [/tex] =>  x∈(-∞;[tex] -\frac{1}{2} [/tex])

[tex]6+9x \leq 1 => 9x \leq -5 => x \leq -\frac{5}{9} [/tex] => x∈(-∞;[tex]- \frac{5}{9} [/tex]]

Solutia sistemului este (-∞;[tex] -\frac{1}{2} [/tex]) ∩ (-∞;[tex]- \frac{5}{9} [/tex]] = (-∞;[tex] -\frac{1}{2} [/tex]).

[tex] \left \{ {{3-4x>5} \atop {6+9x\leq1 }} \right. [/tex]⇔[tex] \left \{ {{-4x>2} \atop {9x \leq -5}} \right. [/tex]⇔[tex] \left \{ {{x< \frac{2}{-4} } \atop {x \leq \frac{-5}{9} }} \right. [/tex]⇔[tex] \left \{ {{x< \frac{1}{-2} } \atop {x\leq \frac{-5}{9} }} \right. [/tex]
[tex]s=(-infinit; \frac{-5}{9} ][/tex].