Question

20,1x-1,1=4 (10-5,25x)

Answer 1

20,1x-1,1=4 (10-5,25)
20,1x-1,1=4×4,75
20,1x-1,1=19
20,1x=19+1,1
20,1x=20,1
x=20,1÷20,1
x=1