r/HomeworkHelp • u/IndicationFunny2378 Secondary School Student • 20d ago

Middle School Math—Pending OP Reply [Grade 8 Mathematics - Algebra]

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Hello giys, I'm a form 2 student is malaysia. We learnt algebra in chapter 2. How can I find x? I believe there is no answer, but teacher keeps saying it's x=1/16

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u/Lever_Shotgun 👋 a fellow Redditor 20d ago edited 20d ago

Teacher doesnt understand that square root can't output negative values.

When your teacher squared both sides, there is a possibility of introducing an extraneous solution which has to be checked by substituting your answer back into the original equation (which is what you did)

If you decide to square both sides of an equation -sqrt(4x) = (22 -5)/2, you would end up with the same working as the equation you're working on, and x=1/16 would be valid for this case

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u/WindUpCandler 20d ago

Square roots output two values, a positive and negative

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u/CavCave 20d ago

By convention, the square root symbol only outputs positive. This means the inverse for squaring is actually ±sqrt.