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$$3(x+1) - 7(x+1) = -4x +9$$

How do I solve for $x$?

I get $0x = 13$, which is mathematically impossible...

alkabary
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Andy
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    You are correct. $0x = 13$ is what you should have gotten. This can happen when dealing with equations that you solve for $x$. because it is mathematically impossible, there are no solutions to this equation. – Rick Aug 10 '15 at 22:18
  • Wow! Thanks for the quick response. – Andy Aug 10 '15 at 22:20
  • your result seems to be valid. not any equation has a solution. have you copied the assignment right? – user251257 Aug 10 '15 at 22:20
  • Try graphing the left-hand-side as well as the right-hand-side, and see where the lines cross. – John Joy Aug 11 '15 at 14:18

2 Answers2

1

$$3(x+1) - 7(x+1) = -4x +9 $$

$$3x+3 - 7x-7 = -4x +9 $$

$$-4x = -4x +9 +7-3$$

$$0=13$$

You are correct, this is impossible "False"

3SAT
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1

Your computations are indeed correct and they show that there is no solution to the equation you have to solve.

You can see that as a kind of proof by contradiction. Suppose that there exists a solution to the equation $$3(x+1) - 7(x+1) = -4x +9$$ then this implies that $13=0$ which is a contradiction. Thus the assumption is wrong, i.e. there is no solution to this equation.

Surb
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