Did You Know what Actually is Point of Inflection ? ( Part-2 )

Calculus

From the point \(P(h,2-5h),\ h \in \mathbb{R},\ ( h \neq 1)\) two distinct tangents are drawn to the curve :

\(y={ x }^{ 3 } - { 3x }^{ 2 } - ax +b\).

Find value of \(a + b.\)