Respuesta :

Replace the C and D with 6 and 7.

1/4 (6) + 3 (7)

6/4 + 21 

6/4 + 84/4 = 90/4

90/4 = 22.5

Hope this helps!
1/4(6) + 3(7)
= 1/4 x 6 + 3 x 7
1/4 x 6= 3/2
3 x 7= 21
= 3/2 +21
= 21/1 + 3/2
= 21 x 2/2 + 3/2
=2 x 21 + 3/2
= 45/2