Sam makes x dollars an hour. Every hour she loses 3 dollars in taxes. After five hours, she has 70 dollars in total. How much do
1 answer:
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Answer:
The answer is (b)
Step-by-step explanation:
* Lets check how to find the inverse of the matrix,
its dimensions is 2 × 2
* To know if the inverse of the matrix exist find the determinant
- If its not equal 0, then it exist
* How to find the determinant
- It is the difference between the multiplication of
the diagonals of the matrix
Ex: If the matrix is
its determinant = ad - bc
- After that lets swap the positions of a and d, put negatives
in front of b and c, and divide everything by the determinant
- The inverse will be
* Lets do that with our problem
∵ The determinant = (9 × 9) - (-2 × -10) = 81 - 20 = 61
- The determinant ≠ 0, then the inverse is exist
∴ The inverse is =
* The answer is (b)