Question

Stiind ca numerele x si y sunt direct proportionale cu 3 si 5, calculati 3x+5y/4x-y

Answer 1

(x;y) d.p. (3;5)  =>  x/3=y/5= k  => x=3k si y=5k
                                                                ↓
                        (3x+5y)/(4x-y) = (3*3k+5*5k)/(4*3k-5k)=34k/7k=34/7

Answer 2

(x;y) d.p. (3,5)→x/3=y/5=K
→ x=3K
y=5K

(3x+5y)/(4x-y)=
(3·3K+5·5K) / (4·3K-5K)= (9K+25K)/(12K-5K) =
34K/7K=34/7