Put the number as x and translate the English into math;
(7x+1)/4=9
Then solve for x
8x+1=36
8x=35
x=4.375 or 4 3/8
Hope this helps.
i think this is the answer for n=-2/a+4
-7x + 6 = 27
-7x = 21 (Subtract 6 from both sides)
x = -3 (Divide -7 from both sides)
When you round; you round down if the number in the selected column is below 5 and you round up if the number is 5 and above.
Thus; if you apply this to your question:
784,072 then round up and you get 790,000