Question

Daca u=5xa+3xb+2xc si v=4xa+6xb+7xc,aratati ca u+v este multiplu de 9

Answer 1

u = 5a + 3b + 2c
v = 4a + 6b + 7c

u + v = 5a + 4a + 3b + 6b + 2c + 7x = 9a + 9b + 9c = 9( a + b + c) = multimplu de 9

Answer 2

u=5a+3b+2c
v=4a+6b+7c
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u+v=9a+9b+9c....=> u+v=(a+b+c)*9....=> u+v este multiplu de 9