First, you’ll have to get the the number 21 inside the parentheses like that: ( 2*21 - 21x) + 12x=44
It will become : 42-21x + 12x = 44
Then you bring the X numbers together and put the constant on the other of the equation : (-21x+12x)= 44 - 42
: -9x = 2
So the final answer is x = -2/9