Question

как решить ??????
помогите

Answer 1

$a); ; y(x-2)-x(y+1)=2-3(x-2); ; Rightarrow \\underline {yx}-2y-underline {xy}-x=2-3x+6; ,; ; -2y-x+3x=2+6; ,\\2x-2y=8; |:2\\x-y=4\\b); ; y(x+5)-y(x-2)=-42+4(x+5); ; Rightarrow \\underline {yx}+5y-underline {yx}+2y=-42+4x+20; ,; ; 5y+2y-4x=-42+20; ,\\7y-4x=-22\\c); ; left { {{x-y=4} atop {7y-4x=-22}} right.; ; left { {{x=y+4} atop {7y-4(y+4)=-22}} right.; ; left { {{x=y+4} atop {7y-4y-16=-22}} right. \\left { {{x=y+4} atop {3y=-6}} right.; ; left { {{x=-2+4} atop {y=-2}} right. ; ; left { {{x=2} atop {y=-2}} right.\\Otvet:; ; (2,-2)$