Answer:
Step-by-step explanation:
Given that A is a square matrix and A is idempotent

Consider I-A
i) 
It follows that I-A is also idempotent
ii) Consider the matrix 2A-I

So it follows that 2A-I matrix is its own inverse.
Answer:
Step-by-step explanation:
1. (6/a)x + 5 = 4
(6/a)x = -1
6x = -a
x = -a/6
2. 2ax + 7 = 13
2ax = 6
ax = 3
x = 3/a
3. -ax - 20 = -14
-ax = 6
x = -6/a
No, because the lasts line of the work is not true. 5 and 11 are not equal.
$288 Okay so for a 240 plus a 20 percent is should be 288 dollars. Correctme if im wrong
Answer: 24xy
I'm not sure if I'm right, but if I am and you have any questions about how it was solved, feel free to ask!! :)