Simplified you have 16x-9x which is equal to 7x. So the left side of your equation says 7x-12. This is supposed to be equal to -7x+8. So let's get the x's on one side and solve for x. You did that when you got 14x-12. Then you added the 12. So now you have 14x=20 which if you're solving for x would mean that x= 10/7.
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