Calculate the dot product of D and E, where D=7i - 3j + 2k and E=4i + 5j - 3k. please show working

Since i dot i = 1  and  j dot j = 1 and k dot k = 1 and the other terms are zero

(7 i - 3 j + 2 k) dot (4 i  + 5 j - 3 k) = 28 - 15 -6  = 7

d they tend to lose electrons and become cations.

explanation:

second mirror gathers light from a faraway object and reflects it to another mirror. - a.