Video 00070 Use array formula to solve an algebra equation

Here is an Algebra equation:  9x – 7 = 47

If we know the value of x we can easily determine if the left side = the right side.

But in this case x is not a single value but rather a Domain (a set of numbers).  x can be 5, 6, 7 or 8.  We have four chances to get a true answer.

Here is the Excel formula —>  {=OR(9*{5,6,7,8}-7=47)} 


Here is what happens inside the formula:

Step 1:  Multiply the 9 with each number inside of the array constant:  {=OR({45,54,63,72}-7=47)}

Step 2:  Subtract 7 from each of the numbers inside of the array constant: {=OR({38,47,56,65}=47)}

Step 3:  Compare each number with 47 (TRUE means it’s the same):  {=OR({FALSE,TRUE,FALSE,FALSE})}

Step 4:  The final answer gives us TRUE (The OR function just needs 1 TRUE)


Download my Excel file

Download here or via my OneDrive (file 00070)


Watch my YouTube video   

See how I caught the issue and several ways to fix it.


What are the ingredients to my solution?

OR function, constant array (that contains the 5,6,7,8), entered as an array formula that requires Control Shift Enter (not just enter).


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