Réponse :
[tex]x+11=15\\x+11-11=15-11\\x=4\\\\5x+4=39\\5x+4-4=39-4\\5x=35\\\dfrac{5x}{5}=\dfrac{35}{5}\\x=7[/tex]
[tex]6x-7=11\\6x-7+7=11+7\\6x=18\\\dfrac{6x}{6}=\dfrac{18}{6}\\x=3\\\\5x-2=3x+9\\5x-2+2=3x+9+2\\5x=3x+11\\5x-3x=3x+11-3x\\2x=11\\\dfrac{2x}{2}=\dfrac{11}{2}\\x=5,5[/tex]
Bonne journée.
