(4-square root of 16) +(-7-20) / -2(1-4)^2
This is ambiguous. I will take the problem as it is written. (As it happens there is no difference in the final result between this and the other likely interpretation.)
$\displaystyle (4 - \sqrt{16}) + \frac{-7 - 20}{-2(1 - 4)^2}$
$\displaystyle (4 - 4) + \frac{-27}{-2(-3)^2}$
$\displaystyle 0 + \frac{-27}{-2 \cdot 9}$
$\displaystyle \frac{-3}{-2}$
$\displaystyle \frac{3}{2}$
-Dan