(10x5)+(30+20)x10-100-1
First solve everything in parenthesis.
50+50x10-100-1
Then, because of PEMDAS (Parenthesis, exponent, multiplication/division, addition/subtraction) you need to then do 50x10.
50+500-100-1
Then, because addition and subtraction can be switched around you do 50+500 first.
550-100-1
Then you do 550-100.
450-1
Then you subtract 450-1 and get your answer.
450-1=449
Hope this helps and have a nice day!!!