Question

ajutorr, exercitiul 9..dau 15 puncte

Answer 1

$\frac{a}{ \frac{1}{3} } = \frac{b}{ \frac{1}{5} } = \frac{c}{ \frac{1}{9} } = \frac{d}{ \frac{1}{12} } \\ 2 - 3b + c - d = 5$

$3a = 5b = 9c = 15d \\ 2a - 3b + c - d = 5$

$a = \frac{15d}{3} = 5d \\ b = \frac{15d}{5} = 3d \\ c = \frac{15d}{9} = \frac{5d}{3}$

$2 \times 5d - 3 \times 3d + \frac{5d}{3} - d = 5 \\ 10d - 9d + \frac{5d}{3} - d = 5 \\ \frac{5d}{3} = 5 \\ d = 3$

$d = 3 \\ a = 15 \\ b = 9 \\ c = 5$