we have the expression

we know that
Applying PEMDAS
P ----> Parentheses first
E -----> Exponents (Powers and Square Roots, etc.)
MD ----> Multiplication and Division (left-to-right)
AS ----> Addition and Subtraction (left-to-right)
solve Multiplication First
5x5x6x8=1,200
9x524x8x6=226,368
725x6=4,350
substitute
1,200-6x226,368+9-4,350
solve
6x226,368=1,358,208
1,200-1,358,208+9-4,350
Solve the addition and subtraction
1,200-1,358,208+9-4,350=-1,361,349
answer is
-1,361,349