Question

Daca a supra b =cu 2supra5. Atunci 7a-2bsupra4a+3b

Answer 1

a / b  = 2 / 5 

a / 2 = b / 5 = K
a / 2  = K => a = 2 K
b / 5 = K => b = 5 K

( 7 · 2 K  - 2 · 5 K ) /  ( 4 · 2 K + 3 · 5 K  ) = 
= ( 14 K - 10 K ) / ( 8 K + 15 K ) 
= 4 K / 23 K
= 4 / 23