Question

stiind ca 2x + 3y/ 6x - y = 7/5, atunci x/y este:
a) 3
b) 1
c) 7/5
d) 11/16

aveti cerinta si in poza
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Answer 1

Salut!:)

( 2x + 3y ) / ( 6x - y ) = 7 / 5

5( 2x + 3y ) = 7 ( 6x - y )

10x + 15y = 42x - 7x

15y + 7y = 42x - 10x

22y = 32x

y = 32x / 22

y = 16x / 11

Înlocuim în x/y

x / 16x / 11 = x /1 : 16x / 11 => x / 1 * 11 / 16x = 11/16

R : d

Bafta! :)

Answer 2

$\it Fie\ \dfrac{x}{y}=k \Rightarrow x=ky\\ \\ \\ Propor\c{\it t}ia\ din\ enun\c{\it t}\ devine:\\ \\ \\ \dfrac{y(2k+3)}{y(6k-1)}=\dfrac{7}{5} \Rightarrow 42k-7=10k+15 \Rightarrow42k-10k=15+7 \Rightarrow \\ \\ \\ 32k=22|_{:2} \Rightarrow 16k=11 \Rightarrow k=\dfrac{11}{16}$