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Kindly clarify my below query

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Intern
Joined: 19 Jan 2019
Posts: 46
Kindly clarify my below query  [#permalink]

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24 Jan 2020, 12:31
m^2=3m

The doubt is why cannot we cancel m on both the sides
i do get it m can be negative but i assume that it negative sign will have effect when m^2<3m or m^2>3m where we will sign change it

kindly clarify my doubt
Intern
Joined: 29 Oct 2019
Posts: 9
Re: Kindly clarify my below query  [#permalink]

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16 Feb 2020, 21:08
1
Hi there,

The concern is not that m can be negative; but that m can be 0.

If m is 0, you cannot cancel it from both sides. Consider this example:
we know 2x0 = 3x0
But, if I cancel 0 from both sides, I get 2 = 3 which is absurd.

Hence, in any equation, never cancel any variable until you know for sure that it's value cannot be 0.

The current equation should be solved as below:

m^2 = 3m
m^2 - 3m = 0
m (m - 3) = 0
Hence, m = 0 or m = 3

Kudos,if this helped.

Posted from my mobile device
Intern
Joined: 19 Jan 2019
Posts: 46
Re: Kindly clarify my below query  [#permalink]

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17 Feb 2020, 05:25
Aaagmat wrote:
Hi there,

The concern is not that m can be negative; but that m can be 0.

If m is 0, you cannot cancel it from both sides. Consider this example:
we know 2x0 = 3x0
But, if I cancel 0 from both sides, I get 2 = 3 which is absurd.

Hence, in any equation, never cancel any variable until you know for sure that it's value cannot be 0.

The current equation should be solved as below:

m^2 = 3m
m^2 - 3m = 0
m (m - 3) = 0
Hence, m = 0 or m = 3

Kudos,if this helped.

Posted from my mobile device

thanks a lot for the detail explanation
Re: Kindly clarify my below query   [#permalink] 17 Feb 2020, 05:25