Răspuns :
[tex]-x+3x+5=3\\\\2x+5=3\\\\2x=3-5\\\\2x=-2\\\\x=-2\div2\\\\\boxed{\boxed{x=-1}}[/tex]
-x+3x+5=+3
(-x) + (+3x) + (+5) = (+3)
(-2x) + 5= 3
-2x= 5-3
-2x=2
x= -2 :2
x= -1
(-x) + (+3x) + (+5) = (+3)
(-2x) + 5= 3
-2x= 5-3
-2x=2
x= -2 :2
x= -1