Question

Daca x/y=2/5 atunci aflati valoarea rapoartului 2x+3y/7x-2y

Answer 1

x/y=2/5

x=2k

y=3k

2x+3y/7x-2y=

=2×2k+3×3k/7×2k-2×3k=

=4k+9k/14k-6k=

=13k/8k=13/8

Answer 2

Răspuns:

Explicație pas cu pas:

x/y = 2/5 ⇒  5 x = 2 y => produsul mezilor = produsul extremilor

=> x/2 = y/5 = k ->  coeficient de proportionalitate

=>  x = 2 k  si y = 5 k

_____________________________

( 2 x + 3 y ) / ( 7 x - 2 y ) = 19/4

= ( 2×2 k+ 3×5 k ) / ( 7×2k - 2×5k) =

= (4k + 15k)/(14k - 10k ) =

= 19k/4k =

= 19/4