Question

Numerele a si b sunt invers proportionale cu 5 si 3. Calculati valoarea raportului 3a+b supra 2b-a. Va rog, am nevoie urgent ! Multumesc !

Answer 1

Răspuns:

{ a , b } i.p { 5 , 3 }

5a = 3b = K

5a = K => a = K / 5

3b = K => b = K / 3

( 3a + b ) / ( 2b - a ) = ( 3 · K / 5 + K / 3 ) / ( 2 · K / 3 - K / 5 )

= ( 3K / 5 + K / 3 ) / ( 2K / 3 - K / 5 )

= ( 9K / 15 + 5K / 15 ) / ( 10K / 15 - 3K / 15 )

= ( 14K / 15)  / ( 7K / 15 )

= ( 14K / 15 ) · ( 15 / 7K )

= 2 / 15 · 15 / 1

= 2 / 1 · 1 / 1

= 2