Let f(x)=3x2−7x+c , where ‘c’ is a variable co-efficient and x>76 . The value of ‘c’ such that f(x) touches f−1(x)  is

f(x) and f−1(x)  can only intersect on the line y=x                ∴y=x  must be tangentSolving 3x2−7x+c=x p⇒ 3x2−8x+c=0 The above equation has real and equal roots⇒ 64−12c=0 c=163