Вы имели в виду так? х умножается на дробь?
(1/7)•х + (3/14)•х=14
х(1/7 + 3/14)=14
х(2/14+3/14)=14
х•(5/14) = 14
х=14 : 5/14=14•14/5=39,2
Или так? Х в знаменателе?
1/7х + 3/14х=14
(1/х)•(1/7 + 3/14)=14
(1/х)• (2/14 + 3/14)=14
(1/х)•(5/14)=14
х=5/14 : 14
х= 5/196
-18+21/22= -18*22+21/22=-396+21/22=-375/22
1) 3 + cos(y)*y' - 5*y' = 0;
3 = y'(5 - cos(y));
y' = 3/(5 - cos(y));
2)y'' = -(3*(sin(y)*y')/(5-cos(y))^2 = (-9*sin(y))/(5 - cos(y))^3
Y`=((x-5)/(x²+11))`=0
((x²+11)-(x-5)*2x)/(x²+11)²=0
(x²+11-2x²+10x)/(x²+11)²=0
(-x²+10x+11)/(x²+11)=0
-x²+10x+11=0 I×(-1)
x²-10x-11=0 D=12
x₁=11 x₂=-1
y(11)=(11-5)/(11²+11)=6/132=1/22=ymax
y(1)=(1-5)/(1²+11)=-4/112=-1/3=ymin