Answer: x = -1
Explanation:
i assume you mean
5x-(5x+3) = -1/3(12x+21)
lets start with the left
-(5x+3) can be turnd into -5x-3
now it is
5x-5x-3 and that can be just -3
now lets go to the right and get rid of the 1/3
we see the 3 at the bottom of 1/3, and (12x+21) can be factored with 3
so 1/3 x 3(4x+7) is what we get
1/3 x 3 cancels out so we are left with
-3 = (-4x-7)
lets try to get -4x by itself
if you move -4x to the left, turning it into 4x, and move -3 to the right, turning it into 3, you get 4x = -7 +3
-7 +3 = -4
4x = -4
devide by 4
4x/4 = -4/4
x = -1