Question 6173
Let me split it up and compute the variables first.
{{{x^2}}} = {{{(-2)(-2)=4}}} to multiply 2 negative signs equals a positive.
{{{y^2}}} = {{{(5)(5)=25}}}
{{{z^3}}} = {{{(-1)(-1)(-1)=-1}}} as a tip to remember: if the number of negatie signs to multiply is an odd number (here 3) then the answer is negative. 
{{{y}}} = {{{5}}}
Now let's substitute the variables for the computed values.
{{{5(4)(25)(-1)-(4)(5)}}} and we get
{{{-500-20}}} which equals to
{{{-520}}}
Hope this helps