To solve the system
[tex] \left\{\begin{array}{c}
2x+y-10=0 \\
x-y-4=0
\end{array}\right. [/tex]
you have to add both equations:
[tex] 2x+y-10+x-y-4=0+0,\\ 3x-14=0,\\ 3x=14,\\ \\x=\dfrac{14}{3} [/tex].
Substitute this x-value into second equation:
[tex] \dfrac{14}{3} -y-4=0,\\ y=\dfrac{14}{3} -4=\dfrac{14-12}{3}=\dfrac{2}{3} [/tex].
The solution of the system is x=14/3 and y=2/3.
Answer: y=2/3, correct choice is B.
