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x-x-1-2-x-1-3-8-2x-8-x-1-3-k-k-2-x-lt-k-1-2-8-k-1-3-x-lt-9-k-1-3-k-2-lt-28-3k-3-9k-lt-56-k-lt-56-9-




Question Number 169768 by mnjuly1970 last updated on 08/May/22
        [x]+[x+(1/2)]+[x−(1/3)]= 8       [2x]=8−[x−(1/3)]=k           (k/2)≤x<((k+1)/2) ,     8−k+(1/3)≤x <9−k+(1/3)            (k/2) < ((28−3k)/3)  ⇒ 9k < 56               k <((56)/9)    ★                 ((25)/3) −k<((k+1)/2) ⇒ 50−6k<3k+3      ⇒     ((47)/9) <x  ★★     ★  & ★★ :     k=6                 3≤x< (7/2)        (1)                (7/3)≤x< ((10)/3)      (2)     (1) & (2)      ⇒      (7/3)≤x<((10)/3)
$$\:\:\: \\ $$$$\:\:\:\left[{x}\right]+\left[{x}+\frac{\mathrm{1}}{\mathrm{2}}\right]+\left[{x}−\frac{\mathrm{1}}{\mathrm{3}}\right]=\:\mathrm{8} \\ $$$$\:\:\:\:\:\left[\mathrm{2}{x}\right]=\mathrm{8}−\left[{x}−\frac{\mathrm{1}}{\mathrm{3}}\right]={k} \\ $$$$\:\:\:\:\:\:\:\:\:\frac{{k}}{\mathrm{2}}\leqslant{x}<\frac{{k}+\mathrm{1}}{\mathrm{2}}\:,\:\:\:\:\:\mathrm{8}−{k}+\frac{\mathrm{1}}{\mathrm{3}}\leqslant{x}\:<\mathrm{9}−{k}+\frac{\mathrm{1}}{\mathrm{3}} \\ $$$$\:\:\:\:\:\:\:\:\:\:\frac{{k}}{\mathrm{2}}\:<\:\frac{\mathrm{28}−\mathrm{3}{k}}{\mathrm{3}}\:\:\Rightarrow\:\mathrm{9}{k}\:<\:\mathrm{56} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:{k}\:<\frac{\mathrm{56}}{\mathrm{9}}\:\:\:\:\bigstar \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\frac{\mathrm{25}}{\mathrm{3}}\:−{k}<\frac{{k}+\mathrm{1}}{\mathrm{2}}\:\Rightarrow\:\mathrm{50}−\mathrm{6}{k}<\mathrm{3}{k}+\mathrm{3} \\ $$$$\:\:\:\:\Rightarrow\:\:\:\:\:\frac{\mathrm{47}}{\mathrm{9}}\:<{x}\:\:\bigstar\bigstar \\ $$$$\:\:\:\bigstar\:\:\&\:\bigstar\bigstar\::\:\:\:\:\:{k}=\mathrm{6} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\mathrm{3}\leqslant{x}<\:\frac{\mathrm{7}}{\mathrm{2}}\:\:\:\:\:\:\:\:\left(\mathrm{1}\right) \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\frac{\mathrm{7}}{\mathrm{3}}\leqslant{x}<\:\frac{\mathrm{10}}{\mathrm{3}}\:\:\:\:\:\:\left(\mathrm{2}\right) \\ $$$$\:\:\:\left(\mathrm{1}\right)\:\&\:\left(\mathrm{2}\right)\:\:\:\:\:\:\Rightarrow\:\:\:\:\:\:\frac{\mathrm{7}}{\mathrm{3}}\leqslant{x}<\frac{\mathrm{10}}{\mathrm{3}} \\ $$$$\:\:\:\:\:\:\:\: \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\: \\ $$

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