Find the gross profit 8 Find the matrix X so that 
1
2
3
7
8
9
X 4
5
6
2
4
6
−
−
−




=








Choose the correct answer in the following questions:
9 If A =                 is such that A² = I, then
(A) 1 + α² + βγ = 0
(B) 1 – α² + βγ = 0
(C) 1 – α² – βγ = 0
(D) 1 + α² – βγ = 0
10