Răspuns:
Explicație pas cu pas:
x/y = 2/5 => 5 x = 2 y => x/2 = y/5 = k -> coeficient de proportionalitate
=> x = 2 k si y = 5 k
______________________________________________________
a) 3x/4y = ( 3×2k)/(4×5k)= 6k/20k = (6/20)⁽² = 3/10
________________________________________
b)
(3x+2y)/3y = 16/15
= (3×2k + 2×5k) / (3×5k) =
= ( 6 k + 10 k ) /15k =
= 16k/15 k =
= 16/15
___________________________
c)
(2 x + 3 y ) / ( 7 x - 2 y ) = 19/4
= ( 2×2k + 3×5k) /( 7×2k - 2×5k ) =
= ( 4 k + 15 k ) / ( 14 k - 10 k ) =
= 19 k / 4 k =
= 19/4
