Yg no 4 gimana ya ?

[tex] \left[\begin{array}{ccc}a&\\0\\a\end{array}\right] [/tex] - [tex] \left[\begin{array}{ccc}-2b&\\2b\\0\end{array}\right] [/tex] + [tex] \left[\begin{array}{ccc}0&\\-c\\c\end{array}\right] [/tex] =[tex] \left[\begin{array}{ccc}1&\\2\\1\end{array}\right] [/tex]

a+2b = 1
-2b-c = 2
a+c= 1
a+2b = a+c
2b = c
sub 2b = c ke -2b-c = 2
-2c = 2
c= -1
sub c= -1 ke a+c= 1
a = 2
sub c= -1 ke 2b = c
b = -1/2
maka :
a = 2
b = -1/2
c = -1
a+b+c = 1/2