Répondre :

B=6a-8a²-15+20a-10+2a

=-8a²+28a-25

 

C=-3z+6+4z²-8z

=4z²-11z+6

 

D=-10r+15r²-2r²-5r-4r-10

=13r²-19r-10

 

voila

B=6a-8a²-15+20a-10+2a

=-8a²+28a-25

 

C=-3z+6+4z²-8z

=4z²-11z+6