Excel 代數計算Formula

首先, 你可以將Y set 做其他cell e.g. C1
咁樣既話:
A1 = 120
B1 = A1- (( C1 x 15%) + (C1 x 4%))
C1 = 任何一個數

然後用"工具" --> "目標搜尋"
目標儲存格 = B1
目標值 = 你要既答案
變數儲存格 = C1

咁excel就會自動幫你搵C1 (即係Y) 既value

呢一個excel function (目標搜尋, or goal seek) 只係用於一個未知數上
若然你有多過一個未知數就唔可以用goal seek
而要用excel add-in 既function "Solver" 啦 :D

按 spcheater 的方法已可以計算到你要的答案.

至於 EXCEL 係點計出嚟, 呢個就.... 好有可能係不斷代入數值去計...

唔可能期望 EXCEL 可以逐步解題卦...

120 - ((Y x 15% ) + (Y x 4%)) = 0
((Y x 15%) + (Y x 4%)) = 120
Y x (15% + 4%) = 120
Y x 19% = 120
Y = 120 / 19%
Y = 631.58

First of all you have to decide where to put the Y in your spreadsheet. As the cell where you will put the number of Y, I have marked it as $B$2 due to this is the assign cell where you will put the numuber of Y. As you have mentioned, 120 is a fixed number in cell A1, therefore, $A$1 is the fixed cell to reflect 120. Don't forget to put = in the begining as the spreadsheet only recognize formula with a =

=$A$1-(($B$2*15%)+($B$2*4%))