First, we have to bring the negative 8 to the other side to make it positive .
4=-8+3x
+8=+8
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12= 3x
We then add 4+8 =12 and bring the 3x down .Second , we divide 3x by 3 to cancel out and do the same to the other side by dividing 12 by 3.
12= 3x
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3 3
4 = x
Lastly, after dividing u will get 4 which is x
Hope this helped!