Answer :

[tex]2(2-j)=4(j+10)\\ 4-2j=4j+40\\ -6j=36\\ j=-6[/tex]
2(2-j)= 4 ( j + 10)
Steps:
1. Multiply everything in parentheses
4 + -2j= 4j + 40
2. Add 2j on both sides
4= 6j + 40
3. Subtract 40 on both sides
-36= 6j
4. Divide by 6
5. Your answer is
J= -6