Answer:
Therefore,

Step-by-step explanation:
Given:
![A=\left[\begin{array}{ccc}3&6&9\\2&4&8\\\end{array}\right]](https://tex.z-dn.net/?f=A%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D3%266%269%5C%5C2%264%268%5C%5C%5Cend%7Barray%7D%5Cright%5D)
To Find:
a₂₁ = ?
Solution:
Let,
![A=\left[\begin{array}{ccc}a_{11}&a_{12}&a_{13}\\a_{21}&a_{22}&a_{23}\\\end{array}\right]](https://tex.z-dn.net/?f=A%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Da_%7B11%7D%26a_%7B12%7D%26a_%7B13%7D%5C%5Ca_%7B21%7D%26a_%7B22%7D%26a_%7B23%7D%5C%5C%5Cend%7Barray%7D%5Cright%5D)
We require ' a₂₁ ' i.e Second Row First Column Element
So on Comparing we get
∴ 
Therefore,

45+(45*.15)=
45+6.75=51.75
6.75 is the tip, 51.75 is the total bill
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Answer:
-15.96
Step-by-step explanation:
A conjugate is a binomial with the sign inside changed. So the conjugate of (1/5 + 4i) is (1/5 - 4i)
Set the original and the conjugate next to each other and F.O.I.L. Multiply the first numbers of each binomial, the 1/5 and the 1/5 to get 1/25. This is the "F."
Multiply the outer members, the 1/5 and the 4i to get - 60i. This is the "O."
Multiply the inner numbers ( the + 4i and the 1/5) to get + 60i. This is the "I."
Multiply the positive 4i and the negative 4i to get 16i squared
The positive 60i and the negative 60i cancel each other out.
The i squared changes into - 1. This makes the 16 negative.
Add 1/25 to - 16 to get - 15.96