Question

Daca x+y = 18 si x/y = 4/5, atunci determina x si y.

Answer 1

x+y = 18

x/y = 4/5=>x=4y/5

si inlocuim in suma:

4y/5+y=18

aducem la acelasi numitor si il eliminam

4y+5y=90

9y=90

y=10

deci x=4*10/5=4*2=8

Answer 2

x+y=18

x/y=4/5=k

x=4k

y=5k

4k+5k=18

9k=18

k=18:9

k=2

x=4×2

x=8

y=5×2

y=10