Tolong dong bantu jawab nomer 1 dan 4 dong

1) KX=L
    (2  -4)   ·   (a    b )    =(3   3)
    (8  -3)       (c    d)       (-1  4)
↔2a-4c=3
↔8a-3c=-1
↔2b-4d=3
↔8b-3d=4

eliminasi
2a-4c=3  (x4)  8a-16c=12
8a-3c=-1 (x1)  8a-3c=-1
                    -----------------  -
                         -13c=13
                              c=-1
subtitusi
2a-4c=3
2a-4(-1)=3
2a=3-4
a=-1/2

eliminasi
2b-4d=3 (x4) 8b-16d=12
8b-3d=4 (x1) 8b-  3d=4
                   --------------- -
                       -13d=8
                            d=-8/13

subtitusi
2b-4d=3
2b-4(-8/13)=3
2b=3-32/13
2b=7/13
 b=7/26
 

X= (-1/2  7/26)
     (-1    -8/13)