Let the required positive number is x.
The square of the number is [tex]x^2[/tex]
Now, we have been given that square of a positive number decreased by twice the number. It means we have
[tex]x^2-2x[/tex]
Now, it is equal to 48. Hence, we have
[tex]x^2-2x=48\\ x^2-2x-48=0\\ x^2-8x+6x-48=0\\ x(x-8)+6(x-8)\\ (x-8)(x+6)=0\\ x=8,-6[/tex]
The number is positive, Hence, we have [tex]x=8[/tex]
Therefore, the required number is 8
