Rozwiąż układ równań: A)  [latex] left { {{3x+y=3} atop {2x+y=4}} ight. [/latex] B)  [latex] left { {{2x+3y=2} atop {2x-5y=18}} ight. [/latex] C)  [latex] left { {{2x+3y=-18} atop {-3x+y=16}} ight. [/latex]

Odpowiedź w załączniku ;)

A. [latex] left { {{3x+y=3} atop {2x+y=4}/*(-1)} ight. \ left { {{3x+y=3} atop {-2x-y=-4} ight \ x=-1 \ 3* (-1)+y=3 \ -3+y=3 \ y= 3+3 \ left { {{y=6} atop {x=-1}} ight. [/latex] B. [latex] left { {{2x+3y=2} atop {2x-5y=18 /* (-1)}} ight.\ left { {{2x+3y=2} atop {-2x+5y=-18}} ight. \ 8x=16 /:8 \ x=2 \ 2*2+3y=2 \ 4+3y=2 \ 3y=2-4 \ 3y= -2 \ left { {{y=1.5} atop {x=2}} ight. [/latex] C. [latex]left { {{2x+3y=-18} atop {-3x+y=16}} ight. \ left { {{2x+3y=-18} atop {y=16+3x}} ight. \ 2x+3* (16+3x)=-18 \ 2x+48+9x=-18 \ 11x=-18-48\ 11x= -66 /:11 \ left { {{x=-6} atop {y=16+3x}} ight. \ y=16+3*(-6) \ y= 16+ (-18) \ left { {{y=-2} atop {x=-6}} ight. [/latex]