A=[1 17 12 -5
    3 8 -3 12
    0 1 4 2
    5 8 13 1];
b=[1 17 -2 4/5];
determinant=det(A)
transponeeritud=A'
poord=inv(A)
korrutis1=inv(A)*A
korrutis2=A*inv(A)
A*b'
C=A^2+A.*A-inv(A)
vastus3=A*inv(C)+C
((A(2,3)+A(3,2))/(A(4,1)-A(1,4)))^3*(C(1,2)/C(2,1))^-2+b(1)*b(4)