Question

va rog muuult,ajutati-maaaa.Macar catevaaaaa

Answer 1

$2a + \: 2b + \: 2c = a + b + c = 7 = (a + b + c) \times 2 = 7 \times 2 = 14 \: puctu \: a$
$a + b + c = 7 = 10a + 10b + 10c = 7 \times 10 = 70 \: puctu \: b$
$a \times 13 + b \times 13 + c \times 13 = 13a + 13b + 13c \: = (a + b + c) \times 13 = 7 \times 13 = 91puctul \: b$
ex 31