because the first thing you do is parenthesis, but there is nothing to do in the parenthesis, the first thing you do in this equation is the exponent. you do 2^3, which is 8. You are left with 4(8)-2(4)^2
4^2 is 16. you are left with 4(8) - 2(16).
4 times 8 = 32
2 times 16 = 32
32-32=0