Answer:
[tex]\large\boxed{j = -12}[/tex]
Step-by-step explanation:
-12 + 6j = 7j
Subtract 6j from both sides of the equation
[tex]\large\boxed{j = -12}[/tex]
This kind of equation can usually be solved by moving the numbers to the opposite side of the equation as the variables.
Hope this helps :)