30. C & D
31. She initially had $30... The cost of each song was $1.20
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Answer:
B. The vectors v and w are orthogonal because their dot product is <u> 0 </u>
Step-by-step explanation:
Given that :
v= - i - j
w= - i + j
Therefore;
vw = ( - i - j ) ( - i + j )
Taking each set of integer of the vector into consideration:
vw = ( -1 × - 1) ( -1 × 1)
vw = 1 - 1
vw = 0
Hence, we can conclude that :
The vectors v and w are orthogonal because their dot product is <u> 0 </u>