Respuesta :

cross multiply
4x - 1 = 21
4x = 22
  x = 22/4
  x = 11/2

answer
D. 11/2

Answer:

11/2

Step-by-step explanation:

First you times the 7 by the three to get rid of the three, then you att one from -1 to get 0 and you also add 1 to 21. then you divide 22 by 4 to get 5.5, then when you turn 5.5 into a fraction you get 11/2.