Найти частные производные первого порядка функций двух переменных

A)zx'=(x-yx+3y)x'=x-yx'∙x+3y-x-3yx'∙x-yx+3y2=12x-y∙1∙x+3y-1∙x-yx+3y2=12∙x+3yx-y - x-yx+3y2= 5y-x2∙x-yx+3y2 ;
zy'=(x-yx+3y)y'=x-yy'∙x+3y-x-3yy'∙x-yx+3y2=12x-y∙1∙x+3y-3∙x-yx+3y2=-3y-x2∙x+3y2∙x-y - 3∙x-yx+3y2= 3y-7x2∙x-yx+3y2;
б) zx'=( x2∙y2-x2∙y+y2)x'=y2∙2x-y∙2x=2xy2-2xy;
zy'=( x2∙y2-x2∙y+y2)y'=x2∙2y-x2+2y=2x2y-x2+2y;
в)zx'=(8-7x+2y)x'=8-7x+2y∙ln8∙2y-7xx'=-7∙ln8∙8-7x+2y;
zy'=(8-7x+2y)y'=8-7x+2y∙ln8∙2y-7xy'=2∙ln8∙8-7x+2y;

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