a) [latex] left { {{3x-y=-40} atop {2x+5y=13}} ight. [/latex] [latex] left { {{3x-y=-40|*5} atop {2x+5y=13}} ight. [/latex] [latex] left { {{15x-5y=-200} atop {2x+5y=13}} ight. [/latex] +----------- 17x=-187 x=-11 y=7 [latex] left { {{3x-y=-40} atop {2x+5y=13}} ight. [/latex] [latex] left { {{-y=-40-3x} atop {2x+5y=13}} ight. [/latex] [latex] left { {{y=-40+3x} atop {2x+5y=13}} ight. [/latex] [latex] left { {{-y=-40-3x} atop {2x+200+15x=13}} ight. [/latex] [latex] left { {{-y=-40-3x} atop {17x=-187}} ight. [/latex] [latex] left { {{y=7} atop {x=-11}} ight. [/latex] Latwiej metoda przeciwnych wspolczynnikow b) [latex] left { {{2x+3y=-1|*-2,5} atop {5x-5y=-90}} ight. [/latex] [latex] left { {{-5x-7,5y=2,5} atop {5x-5y=-90}} ight. [/latex] [latex] left { {{-12,5=-87,5} atop {5x-5y=-90}} ight. [/latex] +------------------- y=7 x=-11 [latex] left { {{-5x-7,5y=-2,5} atop {5x-5y=-90|:5}} ight. [/latex] [latex] left { {{-5x-7,5=-2,5} atop {x-y=-18}} ight. [/latex] [latex] left { {{90+5y-7,5y=2,5} atop {x=-18-y}} ight. [/latex] [latex] left { {{-2,5y=87,5} atop {x=-18-y}} ight. [/latex] [latex] left { {{y=7} atop {x=-11}} ight. [/latex] Latwiej metoda podstawiania
