Răspuns :
Răspuns:
x/y=4/9 ; (7 x 4+4 x 9)/(5 x 4-2 x 9)=(28+36)/(20-18)=64/2=32
Explicație pas cu pas:
x/y=0,(4)
x/y=4/9
9x=4y
x=4y/9
(7x+4y)/(5x-2y)=
=(7*4y/9+9*4y/9)/(5*4y/9-9*2y/9)
=(28y/9+36y/9)/(20y/9-18y/9)
=(64y/9)/(2y/9)
=64y/9*9/2y
=64y/2y
=64/2
=32