Antwort
(1-×)9 =144 |TU
9-9x =144 |:9
1-x = 16 |+x
1= 16+x |-16
-15= x
(1-×)9 =144 |TU
9-9x =144 |:9
1-x = 16 |+x
1= 16+x |-16
-15= x