Question Number 216786 by mnjuly1970 last updated on 20/Feb/25
Answered by mehdee7396 last updated on 21/Feb/25
$${suppose}\:\:{a},{b},{c}\in{A} \\ $$$${a}+{b}={p}\:\:\left({i}\right)\:\:\&\:\:{a}+{c}={q}\:\:\left({ii}\right)\:\:\&\:\:\:{b}+{c}={m}\:\:\left({iii}\right)\:;\:{p},{q},{m}\in{Q} \\ $$$$\left({i}\right)−\left({ii}\right)\rightarrow{b}−{c}={p}−{q}\:\:\left({iv}\right) \\ $$$$\:\left({iv}\right)+\left({iii}\right)\rightarrow\mathrm{2}{b}={p}−{q}+{m}\in{Q}\:\:\: \\ $$$$\Rightarrow{b}\in{Q}\:\:{it}\:{is}\:\:{incorrect}\: \\ $$$$ \\ $$
Commented by mnjuly1970 last updated on 21/Feb/25
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