One more option (similar to Glenn's without the name) if B8=50:
=IRR((A8,B8,B8,B8,B8))

[Maybe of interest: if({1},A1:A2) is different from if(1,A1:A2),
the first converts the reference to an array e.g. try N() on both.]


" wrote:

I am trying to use a cell reference within an array, but Excel won't
let me.

In my case, here is the formula I want: =IRR(A8,50,50,50,50)

A8 is a negative number that will change by row: the next line would
read =IRR(A9,50,50,50,50)

Ideas?