-\text{a0} (a-y(x))^2 (b-y(x))^2 (c-y(x))^2-\text{a2} (a-y(x))^2 (c-y(x))^2-\text{a3} (a-y(x))^2 (b-y(x))^2+2 (a-y(x)) (b-y(x)) (c-y(x)) y''(x)+y'(x)^2 ((a-y(x)) (b-y(x))+(a-y(x)) (c-y(x))+(b-y(x)) (c-y(x)))-\text{a1} (b-y(x))^2 (c-y(x))^2=0