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Everyone knows that whenever we square a negative number it becomes positive but everyone just accepts this as a universal truth. I want to know why this happens? I also want to know as to why do two negatives make a positive? And moreover is (-2)^2=4=(2)^2 then how will be justify that this does not make -2=2 ?

Blue
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FastAndTheCurious
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    It follows simply from the sign rule "minus times minus equals plus" , note that $x^2$ is the same as $x\cdot x$ – Peter Apr 18 '21 at 06:28
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    Squaring an equation is no equivalence transformation. In fact $x^2=4$ has two distinct real solutions. The square root (here of $4$) is defined as the non-negative solution, here $2$. – Peter Apr 18 '21 at 06:31

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