Answer:
see explanation
Step-by-step explanation:
a bit more info is needed so this may be wrong.
so first you add up the x values which is 12x+8x+x=21x
then you can see we have a problem, we dont know the x value so the answer would be 21x +3
but we can go a bit further to get an answer as 3(7x+1)
this is also known as factorisation.
so ans: 3(7x+1)
