let $a=($:$2,5,-5$:$)$ and $b=($:$3,-2,-1$:$).$

$($a$)(2$ pts$)$ Find a$.$b

$($b$)(2$pts$)$ Find $ab.$

$($c$)(2$ pts$)$ Find the magnitude of a and $b.$

$($d$)(2$ pts$)$ Find the unit vector in the direction of a$.$

$($e$)(2$ pts$)$ Find $Pro{j}_{a}b.($the vector projection of $b$ onto $a).$