If you need to solve for x, let's distribute first:
[tex] -4 =\frac{3x}{2}-21[/tex]
Now add 21 to both sides:
[tex] 17 =\frac{3x}{2} [/tex]
Multiply both sides by 2:
[tex] 34=3x [/tex]
Divide by 3, to get your answer:
[tex] \frac{34}{3} = x = 11.33 [/tex]
So, your answer is x = 11.33. Hope I could help!