Réponses

  • Utilisateur Brainly
2013-05-15T15:00:54+02:00

3.5+3.5+x+x=20

7+2x=20

7+2x-7=20-7

2x=13

x=13/2

x=6.5

 

verification: 3.5+3.5+6.5+6.5=20

 

voilà...... :)