Suppose f(x) is the function 2x^3+ 12x^2+

Question

21x + 3. Find the smallest value of f at which the tangent to the curve is 3.

I did:

f'(x)+ 6x^2+ 24x + 21= 3

= 6(x+3)(x+1), x= -3, -1

the correct answer is supposed to be -8

Answer 1

"Find the smallest value of f at which the tangent to the curve is 3."

Check the values of f(-3) and f(-1) and you'll get the right answer!