Because it’s in brackets you multiply 85 by all numbers inside it first:
85*(-5x)= -425x
85*12.5 = 1062.5
85*7.5x= 637.5x
Leaving us with: -425x + 1062.5 + 7.5x
Only like terms can add or subtract from each other, so:
-425x - 7.5x = -432.5
Minus because we move the 7.5x to the left and when moving numbers we change their sign :)
So:
-432.5x + 1062.5
(I may not be correct!)