4x²+y²-4x+10y+26=0
4x²-4x+1+y²+10y+25=0
(2x-1)²+(y+5)²=0
(2x-1)²=0,(y+5)²=0
x=1/2
y=-5
6x-1/5y
=6*(1/2)-1/5*(-5)
=3+1
=4