Question

What is the minimum value of y=(4x+2)(4x-2)+3?

Answer 1

f(x)=16x^2 -4+3
differentiate on both sides
f'(x)=32x
f"(x)=32
so for extreme values f'(x)=0
so x=0
and here minimum value at x=0
f(0) = -1
-1 is the answer .?

Answer 2

Thanks

Answer 3

hope u understand the first order and second order derivative tests for local minima and maxima