Question

determinati nr a si b stiind ca sunt direct proportionate cu 2 si 7 iar diferenta lor este 85

Answer 1

a=2k

b=7k

a-b=85

-5k=85

k=-17

a=-34, b=-119

Sper că te-am ajutat :)

Answer 2

$\it \{a,\ \ b\} \ d.\ p. \ \{2,\ 7\} \Rightarrow \dfrac{a}{2}=\dfrac{b}{7} \Rightarrow b=\dfrac{7a}{2} \Rightarrow b=3,5a\ \ \ \ \ (1)\\ \\ \\ b-a=85\ \ \ \ (2)\\ \\ \\ (1),\ (2) \Rightarrow 3,5a-a=85 \Rightarrow 2,5a=85|_{:5} \Rightarrow 0,5a=17|_{\cdot2} \Rightarrow a=34\ \ \ \ (3)\\ \\ \\ (1),\ (3) \Rightarrow b=3,5\cdot34 \Rightarrow b=119$