Respuesta :

If the number is x, then:
6x+1= (x-1)^2

Now we just need to simplify it
6x+1=(x-1)*(x-1)
6x+1=x^2-2x+1
8x=x^2
8=x

The number is 8.

To check the answer
6*8+1=7^2
49=49
correct :)