Question

Daca 2a supra 5v egal 0,7 si 2a+5b=34, determinați numerele a si b.

Answer 1

2a/5b=7/10 => 2a/7=5b/10k => 2a=7k si 5b=10k. 2a+5b=34 => 7k+10k=34 => k=2 => 2a=14 deci a=7 si 5b=20 deci b=4

Answer 2

$\frac{2a}{5b} =0,7$
$\frac{2a}{5b} = \frac{7}{10}$
2a=$\frac{5b*7}{10}$
$\frac{35b}{10} +5b=34$
35b+50b=340
85b=340
b=4
2a=$\frac{4*5*7}{10} = 14$
2a=14
a=7