Question

-0,9+х= -1 ; 4 ......

Answer 1

-0.9+x=-1
x=0.9-1
x=-0.1
-0.9+x=4
x=4+0.9
x=4.9

Answer 2

1) -0,9+х=-1
х=-1+0,9
х=-0,1
2) -0,9+х=4
х=4+0,9
х=4,9