Question

1)(a•b)•(c•d) stiind cs c=0
2)5•(a+b) stiind ca 5•a+5•b=-100
3)(a+b)•c, daca ac=bc=5.

Answer 1

1) 0
2) 5•(a+b)
5a+5b
5a+5b=-100
3) (a+b)•c
ca+cb
5+5=10