Question

EXPLAIN AND THEN ANSWER
NO RUBBISH ANSWER
I WELL EXPLAINED I WILL MARK IT AS BRAINLIEST ​

Answer 1

Unit vector is just a vector of length I

Unit vector in the direction of any vector can be calculated just by dividing the vector with its magnitude. Unit vector perpendicular to two given vectors can be found by dividing the cross product of two vectors with its magnitude.

Just as a note, you mean the value of “a”, not the value of “A.” A is given as a fixed vector.

Vectors that are perpendicular to one another have zero inner product:

A . B = 5*2 + 7*2 + 3*a = 0

Note that the last operator is + because both vectors have negative k components; the product of two negatives is a positive.

This is easy to solve:

10 + 14 + 3a = 0

3a = -24

a = -8.

Answer 2

Explanation:

Let the initial money with Amy and Betty be x and y.

★ According to the first condition, Amy had 3 times as much money as Betty.

\longrightarrow⟶ x = 3y ---- (Equation I)

Money left after spending $60 :

Amy = (x – 60)

Betty = (y – 60)

★ According to the second condition,

After spending $60, Amy had 4 times as much money as Betty.

\longrightarrow⟶ (x – 60) = 4(y – 60)

\longrightarrow⟶ x – 60 = 4y – 240

\longrightarrow⟶ 3y – 60 = 4y – 240 ----- (Substitute equation I)

\longrightarrow⟶ 3y – 4y = –240 + 60

\longrightarrow⟶ –y = –180

\longrightarrow⟶ y = 180

Money with Betty = $180

________________________

★ Money with Amy :

Substitute the value of y in equation I.

\longrightarrow⟶ x = 3(180)

\longrightarrow⟶ x = 540

Money with Amy = $540

Therefore, money with Amy