It means 11:30 PM - 5:40 AM .
Answer:
Step-by-step explanation:
1). x² - 8x
To convert this expression into a perfect square trinomial,
x² - 2(4x) + 4² = (x - 2)²
Therefore , 4² = 16 should be added.
Option (4) is the answer.
2). x² + 2x = 3
x² + 2(1)(x) = 3
x² + 2(1)(x) + 1 = 3 + 1 [By adding 1 on both the sides]
(x + 1)² = 4
x + 1 = ±2
x = -3, -1
Option (1) is the answer.
3). 3x²- 18x = 21
x² - 6x = 7
x² - 2(3x) = 7
x² - 2(3x) + 3² = 7 + 3²
(x - 3)² = 7 + 9
(x - 3)² = 16
x - 3 = ±4
x = -1, 7
Answer:
![A)\ \ \ \ \left[\begin{array}{ccc}8&-5\\-3&2\\\end{array}\right]](https://tex.z-dn.net/?f=A%29%5C%20%5C%20%5C%20%5C%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D8%26-5%5C%5C-3%262%5C%5C%5Cend%7Barray%7D%5Cright%5D)
Step-by-step explanation:
Given the matrix: ![\left[\begin{array}{ccc}2&5\\3&8\\\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D2%265%5C%5C3%268%5C%5C%5Cend%7Barray%7D%5Cright%5D)
, it's inverse is calculated using the formula:
![\left[\begin{array}{ccc}a&b\\c&d\\\end{array}\right]^{-1}=\frac{1}{det\left[\begin{array}{ccc}a&b\\c&d\\\end{array}\right] }\left[\begin{array}{ccc}d&-b\\-c&a\\\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Da%26b%5C%5Cc%26d%5C%5C%5Cend%7Barray%7D%5Cright%5D%5E%7B-1%7D%3D%5Cfrac%7B1%7D%7Bdet%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Da%26b%5C%5Cc%26d%5C%5C%5Cend%7Barray%7D%5Cright%5D%20%7D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dd%26-b%5C%5C-c%26a%5C%5C%5Cend%7Barray%7D%5Cright%5D)
#Therefore, we calculate as;
![\frac{1}{det\left[\begin{array}{ccc}2&5\\3&8\\\end{array}\right] }\left[\begin{array}{ccc}8&-5\\-3&2\\\end{array}\right] \\\\\\\\\#det\left[\begin{array}{ccc}2&5\\3&8\\\end{array}\right] =1\\\\\\\\=\frac{1}{1}\left[\begin{array}{ccc}8&-5\\-3&2\\\end{array}\right] \\\\\\\\=\left[\begin{array}{ccc}8&-5\\-3&2\\\end{array}\right]](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7Bdet%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D2%265%5C%5C3%268%5C%5C%5Cend%7Barray%7D%5Cright%5D%20%7D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D8%26-5%5C%5C-3%262%5C%5C%5Cend%7Barray%7D%5Cright%5D%20%5C%5C%5C%5C%5C%5C%5C%5C%5C%23det%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D2%265%5C%5C3%268%5C%5C%5Cend%7Barray%7D%5Cright%5D%20%3D1%5C%5C%5C%5C%5C%5C%5C%5C%3D%5Cfrac%7B1%7D%7B1%7D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D8%26-5%5C%5C-3%262%5C%5C%5Cend%7Barray%7D%5Cright%5D%20%5C%5C%5C%5C%5C%5C%5C%5C%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D8%26-5%5C%5C-3%262%5C%5C%5Cend%7Barray%7D%5Cright%5D)
Hence, the inverse of the matrix is ![\left[\begin{array}{ccc}8&-5\\-3&2\\\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D8%26-5%5C%5C-3%262%5C%5C%5Cend%7Barray%7D%5Cright%5D)
