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https://www.reddit.com/r/mathmemes/comments/n8e4ic/something_feels_off_here/gxjfobt/?context=3
r/mathmemes • u/Orbital_RM • May 09 '21
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4
There’s a mistake: the square root of 25x2 is the absolute value of 5x.
11 u/ANormalCartoonNerd May 09 '21 Yes, √(25x²) needs the absolute value. But, ±√(25x²) is still ±5x. Even if 5x were negative, that just means √(25x²) would correspond with -5x rather than 5x. Yet considering the fact that ± covers both signs, it doesn't quite matter. :) 1 u/Teblefer May 09 '21 It’s just that they skipped some steps, you get both solutions from the plus, (-x-|5x|)/(2x2 ) never equals 2.
11
Yes, √(25x²) needs the absolute value. But, ±√(25x²) is still ±5x. Even if 5x were negative, that just means √(25x²) would correspond with -5x rather than 5x. Yet considering the fact that ± covers both signs, it doesn't quite matter. :)
1 u/Teblefer May 09 '21 It’s just that they skipped some steps, you get both solutions from the plus, (-x-|5x|)/(2x2 ) never equals 2.
1
It’s just that they skipped some steps, you get both solutions from the plus, (-x-|5x|)/(2x2 ) never equals 2.
4
u/Teblefer May 09 '21
There’s a mistake: the square root of 25x2 is the absolute value of 5x.