How to Check a Linear Equation Answer by Substitution
A tidy answer can still be wrong. Put it back into the original equation and make both sides prove it.
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Work the problem.
Then check the work.
Short, careful guides for the moment when your algebra looks right but you are not quite ready to trust it.
How to Check Your Algebra Work and Find the First Wrong Step
A wrong answer tells you something broke. Comparing one line at a time tells you where.
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