Question

va rog ajutati-ma
1. Valoarea lui x din proportia 12/x+1 = 2/3 este....
2. Daca 3x/7 = 2y/5, atunci x/y este egal cu :
A. 7/5 B. 14/15 C. 15/14 D. 7/5

Answer 1

$\it 1)\ \ \dfrac{12}{x+1}=\dfrac{^{6}2}{\ 3}\ \Rightarrow\dfrac{12}{x+1}=\dfrac{12}{18}\ \Rightarrow x+1=18\ \Rightarrow\ x=17\\ \\ \\ 2)\ \ \dfrac{3x}{7}=\dfrac{2y}{5}\ \Rightarrow\ \dfrac{3x}{2y}=\dfrac{7}{5}\ \Rightarrow\ \dfrac{3}{2}\cdot\dfrac{x}{y}=\dfrac{7}{5}\ \Rightarrow\ \dfrac{x}{y}=\dfrac{7}{5}\cdot\dfrac{2}{3}\ \Rightarrow\ \dfrac{x}{y}=\dfrac{14}{15}$