1) Находим производную y ' =2x-4
k=0 , 2x-4=0, x = 2,
y=-4
2) y ' = -2x, k =0, -2x=0, x =0,
y=1
3) y ' =2x, k=0, x= 0
y=0
4 ) y ' =18x-1, k= 0, 18x-1= 0, x = 1/18
y=-1/36
