if (-2 1 x+2 )

(3 x-4 5 ) =25
(0 1 3 )

a) find the value of x

b) hence ,find (-2 1 x+2 )^-1
( 3 x-4 5 )
(o 1 3 )

p/s : all the value above IS COMBINE in one bracket ( )

solve the equations by using

a) the adjoint matrix
b) elementary row operations

i) x+y+z=6
2x-y+z=3
x+4y-z=6

ii) 3p-3q+r=1
-3p+5q-2r=-1
p-2q+r=3

iii)-12a+b+17c=-14
2a-b+3c=5
8a+b-13c=-3

thanks sir/madam