Cc bonne année

1- 8*5+8*x+3
= 40+8x+3
=43+8x

2- 7*4-7*b+9
= 28-7b+9
=37-7b

7*b-7*4+4.3b-5
= 7b-28+4.3b-5
=11.3b-33

7*4-7*b+9
= 28-7b+9
=37-7b

Voila :)