Bonsoir,
Exercice 78.
[tex]a)\ - 2x -3 < 6x -2\\-2x - 6x < -2 +3\\-8x < 1\\\\\boxed{x > -\dfrac{1}{8}}
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[tex]b)\ 3 -5 y \le 12 + 8y\\- 5y - 8y\le12 -3\\- 13y\le 9\\\\y \ge \dfrac{9}{-13}\\\\\boxed{y \ge -\dfrac{9}{13}}[/tex]
Exercice 80.
[tex]a)\ -5(x +3) < x +12\\- 5x - 15 < x +12\\- 5x -x < 12 +15\\-6x < 27\\\\x > \dfrac{27}{-6}\\\\\boxed{x > -\dfrac{27}{6}}[/tex]
[tex]f) -1 - (5y -1) < -6 - ( y +12)\\ -1 - 5y +1 < -6 - y -12\\ -5y + y < -6-12+1-1\\-4y<-18\\\\y>\dfrac{-18}{-4}\\\\\boxed{y>\dfrac{9}{2}}
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Exercice 99.
[tex]1)\ -3x+7=0\\-3x=-7\\\\x=\dfrac{-7}{-3}\\\\\boxed{x=\dfrac{7}{3}}\Longrightarrow \boxed{R\acute{e}ponse\ b}[/tex]
[tex]2)\ 5x+3\ge2x+9\\5x-2x\ge9-3\\3x\ge6\\\\x\ge\dfrac{6}{3}\\\\\boxed{x\ge2}\Longrightarrow \boxed{R\acute{e}ponse\ b}[/tex]
