All real numbers.
Step-by-step explanation:
Distributive property: a(b+c)=ab+ac
Expand: 4(a+2)=4a+8
Expand again: 14-2(3-2a)=4a+8
4a+8=4a+8
You subtract by 8 from both sides of an equation.
4a+8-8=4a+8-8
Simplify.
4a=4a
Then, subtract by 4a from both sides of an equation.
4a-4a=4a-4a
Finally, simplify.
4a-4a=0
0=0
True
All real numbers is the final answer.
Hope this helps you!
Have a nice day! :)