Respuesta :

2d + 13 = 12

d = -0.5

-0.5 × 2 = -1

13 + (-1) = 12

Hope this helped☺☺

Explanations:

Twice a number d and 13 = 2d + 13 

The sum = Total 

Is 12 = "= 12"

That equals :

2d + 13 = 12