$25.$ Given the following, vec$(a)=[-5,-2,6],$ and vec$(b)=[3,-1,-2].$

a$)$ Find vec$(a)$vec$(b).$

$[2$A$]$

b$)$ Find the angle between, vec$(a)$ and vec$(b).$

$[3$A$]$

c$)$ Find proj ${?}_b$vec$(a).$

$[3$A$]$