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Question-186966




Question Number 186966 by 073 last updated on 12/Feb/23
Commented by 073 last updated on 12/Feb/23
solution ?
$$\mathrm{solution}\:? \\ $$
Commented by 073 last updated on 12/Feb/23
i need it please   solution??
$$\mathrm{i}\:\mathrm{need}\:\mathrm{it}\:\mathrm{please}\: \\ $$$$\mathrm{solution}?? \\ $$
Answered by Rasheed.Sindhi last updated on 13/Feb/23
a∗b=2a+2b−ab−(b∗a)  a & b are exchangeable ⇒a∗b=b∗a  2(a∗b)=2a+2b−ab  a∗b=a+b−((ab)/2)  (−2)∗3=−2+3−(((−2)(3))/2)=−2+6=4
$${a}\ast{b}=\mathrm{2}{a}+\mathrm{2}{b}−{ab}−\left({b}\ast{a}\right) \\ $$$${a}\:\&\:{b}\:{are}\:{exchangeable}\:\Rightarrow{a}\ast{b}={b}\ast{a} \\ $$$$\mathrm{2}\left({a}\ast{b}\right)=\mathrm{2}{a}+\mathrm{2}{b}−{ab} \\ $$$${a}\ast{b}={a}+{b}−\frac{{ab}}{\mathrm{2}} \\ $$$$\left(−\mathrm{2}\right)\ast\mathrm{3}=−\mathrm{2}+\mathrm{3}−\frac{\left(−\mathrm{2}\right)\left(\mathrm{3}\right)}{\mathrm{2}}=−\mathrm{2}+\mathrm{6}=\mathrm{4} \\ $$
Commented by 073 last updated on 14/Feb/23
nice solution  thank you
$$\mathrm{nice}\:\mathrm{solution} \\ $$$$\mathrm{thank}\:\mathrm{you}\: \\ $$
Commented by mr W last updated on 16/Feb/23
from  a∗b=2a+2b−ab−(b∗a)  we can not deviate that  a & b are exchangeable ⇒a∗b=b∗a.  we can only say  a∗b+b∗a=2a+2b−ab.    so i think the question is not solvable  with given conditions.
$${from} \\ $$$${a}\ast{b}=\mathrm{2}{a}+\mathrm{2}{b}−{ab}−\left({b}\ast{a}\right) \\ $$$${we}\:{can}\:{not}\:{deviate}\:{that} \\ $$$${a}\:\&\:{b}\:{are}\:{exchangeable}\:\Rightarrow{a}\ast{b}={b}\ast{a}. \\ $$$${we}\:{can}\:{only}\:{say} \\ $$$${a}\ast{b}+{b}\ast{a}=\mathrm{2}{a}+\mathrm{2}{b}−{ab}. \\ $$$$ \\ $$$${so}\:{i}\:{think}\:{the}\:{question}\:{is}\:{not}\:{solvable} \\ $$$${with}\:{given}\:{conditions}. \\ $$
Commented by Rasheed.Sindhi last updated on 16/Feb/23
Thanks a lot sir!
$$\mathbb{T}\boldsymbol{\mathrm{han}}\Bbbk\boldsymbol{\mathrm{s}}\:\boldsymbol{\mathrm{a}}\:\boldsymbol{\mathrm{lot}}\:\boldsymbol{\mathrm{sir}}! \\ $$

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