Răspuns:
a) [tex]\left \{ {{4x+y=10} \atop {x-6y=15}} \right.[/tex]
x=15+6y
4(15+6y)+y=10
60+24y+y=10
25y=-50 /:25 ⇒ y=-2
x=15-2·6 ⇒ x=3
b) [tex]\left \{ {{\frac{x+1}{2}+\frac{x-y}{3} =3} /*6\atop {\frac{x-y+5}{2} =2y+4} /*2\right.[/tex]
[tex]\left \{ {{3x+3+2x-2y=18} \atop {x-y+5=4y+8}} \right.[/tex]
[tex]\left \{ {{5x-2y=15} \atop {x-5y=3}} \right.[/tex]
x=3+5y
15+25y-2y=15
23y=0 ⇒ y=0, x=3
Explicație pas cu pas:
