Sagot :
A=3a+5-8a-7
A=3a-8a+5-7
A=(3-8)a-2
A=-5a-2
B=5-2y+4y+7-6y
B=-2y+4y-6y+5+7
B=(-2+4-6)y+12
B=-4y+12
C=3a+b-a-7-5b+1
C=3a-a+b-5b-7+1
C=(3-1)a+(1-5)b-6
C=2a-4b-6
A= 3a+5-8a-7
A= (3-8)a+(5-7)
A= -3a -2
B=5-2y+4y+7-6y
B= (-2+4-6)y+(5+7)
B= -4y +12
C= 3a+b-a-7-5b+1
C= (3-1)a+(1-5)b+(1-7)
C= 2a-4b-6