Respuesta :

x - (-2) = 21 <== ur equation
x + 2 = 21
x = 21 - 2
x = 19
If it is a number (n) decreased by -2 is equal to 21 then the equation would be
21=n-2
To find n you would add 2 to the other side so 21+2=23
So the full equation with the answer would be
21=23-2