Use PEMDAS. So it would then simplify to [100+(586+4)]/5<19 then continueing that it would be [100+590]/5<19 and then 690/5<19 which finally will be 138<19 and that is a valid statement
Is that negative 2 minus 8? if so put that into the calculator and add 8 to both sides and divide by 2 after that. simple algebra
The charge on each house is 8 units
The answer is 68 because is repeating 3 times