To use all three models:

$$ M$1$: d $=$ a$*$t $+$ b

$$ M$2$: d $=$ a$*$t $+$ b$*$w $+$ c

$$ M$3$: d $=$ a$*$t $+$ b$1$x$1+$ b$2$x$2+$ b$3$x$3+$ b$4$x$4+$ b$5$x$5+$ b$6$x$6+$ c

to predict the demand for seven days ahead $($Mon$,$ Tue, $...,$ Sun$)$ and find the total weekly demand.