Question

find derivative of 2A x square

Answer 1

is it
$2ax {}^{2}$
maybe then i can help.
$\frac{d}{dx} 2ax {}^{2} = 2 \times 2ax {}^{2 - 1} \\ = 4ax$

Answer 2

if derivative is calculated with respect to x then
2A is constant.
so, 2A dx^2/dx
= 2A(2x)
= 4Ax