5x+7y=3
2x-y =4 14x-7y=28
5x+7y+14x-7y=3+28
19x=31 x=31/19
y=2x-4=2*31/19-4 =62/19-4=-14/19
x-2y=4
x+y=5
x-2y-x-y= -1 3y=1 y=1/3
x-2/3=4 x= 4 2/3
[ C - 2/3 (1 - lnx)^(3/2) ]' = -2/3 * 3/2 * (1 - lnx)^(1/2) * (-1/x) = 1/x (1 - lnx)^(1/2)
1)5x-20=x+8
5x-x=-20-8
4x=-28
x=-7
Легко) Решение:
1*0=0
0+1=1