Answer
$t^2-t$
Work Step by Step
The following expression can be written as $$(1-t)^2-(1-t)=(1-t)[(1-t)-1]$$ using the distributive property. Simplify the expression in the brackets to get $$(1-t)(-t)$$ Use the distributive property again to get $$-t(1-t)=-t(1)-t(-t)=t^2-t$$
