[tex] \left \{ {{4x+2y=34\ \ | *2} \atop {10x-4y=-5}} \right. \\\\ \left \{ {{8x+4y=68} \atop {10x-4y=-5}} \right. \\+-----\\addition\ method\\\\
18x=63\ \ \ | divide\ by\ 18\\\\
x=3.5\\\\
2y=34-4x\\\\y=\frac{34-4x}{2}=\frac{34-4*3.5}{2}=\frac{34-14}{2}=\frac{20}{2}=10\\\\ Solution:\\ \left \{ {{y=10} \atop {x=3.5}} \right. [/tex]
