Respuesta :

3(2d - 7) = (2 + 4d)2

distribute

3*2d -3*7 = 2*2 +2*4d

multiply

6d -21 = 4 +8d

subtract 6d from each side

6d-6d-21 = 4 +8d-6d

-21 = 4+2d

subtract 4 from each side

-21 -4 =4+2d-4

-25 =2d

divide by 2

-25/2 =d