C) x+3= 0 <=> x+3-3= 0-3 => x=-3
a) -99r:(-99)= 0:(-99)= 0
b) x+1+x-4= 0 <=> 2x-3=0 <=> 2x=3 => x= 3/2
c) x^2-4= 0 <=> x^2= 4 <=> x= +-2 => x1= -2, x2= 2
d) 3-x+1+3+1= 0 <=> 8-x=0 <=> -x=-8 => x=8
e) Se reduc 3x și -3x => Rezultatul= 1+1= 2
f) x=+-3 => x1=-3, x2=3