Ответ:
Пошаговое объяснение:
проверяем
y=-(0,5x²+C)⁻¹
y'= (0,5x²+C)⁻²*x=x(-(0,5x²+C)⁻¹)²=xy²
Т.к.1сут=24ч,то 1/2сут.=12ч
12ч+1ч=13ч
1)((x+y)/(x-y)-(x²-xy+y²)/(x²+xy+y²)=
=[(x+y)(x²+xy+y²)-(x-y)(x²-xy+y²)/[(x-y)(x²+xy+y²)]=
=(x³+x²y+xy²+xy²+x²y+y³-x³+x²y-xy²=x²y-xy²+y³)/(x³-y³)=
=(4x²+2y³)/(x³-y³)=2y(2x²+y²)/(x³-y³)
2)x(y³-x³)/[y(y²-2x²)(y²+2x²)*2y(2x²+y²)/(x³-y³)=-2x/(y²-2x²)=2x/(2x-y)
2у+7у+78= 1581
9у = 1581 - 78
9у= 1503
у= 1503/9
у= 167
проверим:
2 * 167 + 7 * 167 + 78 = 1581
167 *(2+7) + 78 = 1581
167 * 9 + 78 = 1581
1503 + 78 = 1581
1581=1581
256m - 147m - 1871 = 63747
109m = 63747 + 1871
109m=65618
m= 65618 /109
m=602
проверим:
256 * 602 - 147 * 602 - 1871 = 63747
154112 - 88494 - 1871= 63747
154112-90365=63747
63747=63747