[4-(3-7(7-4)+4)]+7
start with inner most bracket
(7-4) is 3 so replace this bracket with 3
[4-(3-7*3+4)] +7
do the multiplication in the bracket - 7*3 is 21
[4-(3-21+4)]+7
then sort out the bracket (3-21+4) is -14
[4-(-14)]+7
minus minus is +, so 4+14 is 18
18+7 is 25.
Double check this answer by putting it in exactly into a scientific calculator as i might of made a simple mistake somewhere