Respuesta :
D is the answer.
3b+(-2b)= 1b (same as 3-2=1)
4r+(-r)= 3r (same as 4-1=3)
When you add a negative, you subtract.
3b+(-2b)= 1b (same as 3-2=1)
4r+(-r)= 3r (same as 4-1=3)
When you add a negative, you subtract.
The correct answer is (D).
  (3b + 4r) + (-2b - r)    = (3b - 2b) + (4r - r)       = b + 3r
  not
 b + 5r
  * Ella added (4r + r) instead subtracting (4r - r), thus she got the wrong answer.
  (3b + 4r) + (-2b - r)    = (3b - 2b) + (4r - r)       = b + 3r
  not
 b + 5r
  * Ella added (4r + r) instead subtracting (4r - r), thus she got the wrong answer.