Besoin d'aide pour l'exercice 25 et 26 svp

25)
A=1-(4a+5b-3)+4+(-3a-2)
=1-4a-5b+3+4-3a-2
=1-2+4+4-5b-3a
=6-5b-3a
B=(2y-3)+2.7-(7y-1.3)-2
=2y-3+2.7-7y+1.3-2
-5y-1

26)
A=b-(-3b-4)-4+(5b-1)
=b+3a+4-4+5b-1
=6b+3a-1

B=5x-(2x-3)+(7-3x)
=5x-2x+3+7-3x
=10