Bonjour,
Simplifier:
A= -1/15+3/20= (-1x4+3x3)/60= (-4+9)/60= 5/60= (5:5)/(60:5)= 1/12
B=incomplète
C= -5/12+4/15= (-5x5+4x4)/60= (-25+16)/60= -9/60= (-9:3)/(60:3)= -3/20
D= -2/15-3/10= (-2x2-3x3)/30= (-4-9)/30= -13/30
E= -11/20 + 7/12= (-11x3+7x5)/60= (-33+35)/60=2/60= (2:2)/(60:2)= 1/30
F= -2/11 - 5/33= (-2x3-5)/33= (-6-5)/33= -11/33= (-11:11)/(33:11)=- 1/3
