Question

Numerele a si b sunt invers proporționale cu 5 si 8. Daca a+b=26, aflați numerele a si b

Answer 1

{a,b} i. p {5,8}
a/1 supra 5=b/1 supra 8=a/5=b/8=26
a+b/13=26÷13=2
=>a=10, b=16

Answer 2

{a;b} i.p. {5;8}
a/1/5 = b/1/8
5a = 8b ==>a = 8b/5
a + b = 26
8b/5 + b = 26 /×5
8b + 5b = 130
13b = 130
b = 130:13
b = 10
a = 8×10/5 = 8×2 = 16

a = 16
b = 10

verificare:
10+16 = 26
16/1/5 = 10/1/8
5×16 = 8×10
80 = 80