Formula for this?

[Jennyca]

Helllo,

I have an expression that I want to put into a chart on an neat way;
Y1*0.26
Y2*0.18 All=Y
Y3*0.13

W=if X=8 then Y-23.25
W=if X<8 then Y-((23.25/8)*X)
W=if X>8 then Y-23.25-((X-8)*3)

I´m a beginner in Excel so for me it´s dificult.

Thank's

[robert111]

sorry, it is not clear what you want to do