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Câu 5:
\(\dfrac{x+y-2017z}{z}=\dfrac{y+z-2017x}{x}=\dfrac{x+z-2017y}{y}=\dfrac{x+y-2017z+y+z-2017x+x+z-2017y}{z+x+y}=\dfrac{-2015\left(x+y+z\right)}{x+y+z}=-2015\)
\(\Rightarrow\left\{{}\begin{matrix}x+y-2017z=-2015z\\y+z-2017x=-2015x\\x+z-2017y=-2015y\end{matrix}\right.\)\(\Rightarrow\left\{{}\begin{matrix}x+y=2z\\y+z=2x\\x+z=2y\end{matrix}\right.\)
\(P=\left(1+\dfrac{y}{x}\right)\left(1+\dfrac{x}{z}\right)\left(1+\dfrac{z}{y}\right)=\dfrac{x+y}{x}.\dfrac{x+z}{z}.\dfrac{y+z}{z}=\dfrac{2z.2y.2x}{xyz}=8\)
1: \(\left(416-7654\right)-\left(-584+19-654\right)\)
\(=416-7654+584-19+654\)
\(=416+584-7654+654-19\)
=1000-7000-19
=-6019
2: \(\left(214-4864\right)-\left(-192+4214-865\right)\)
\(=214-4864+192-4214+865\)
\(=\left(214-4214\right)+\left(-4864+865\right)+192\)
\(=-4000-4864+864+1+192\)
\(=-4000-4000+193=-8193\)
3: \(\left(-324+1756\right)-\left(2023-4324+756\right)\)
\(=-324+1756-2023+4324-756\)
\(=\left(-324+4324\right)+\left(1756-756\right)-2023\)
\(=4000+1000-2023=5000-2023=2977\)
4: \(\left(-214-248\right)-\left(-695+486-1248\right)\)
\(=-214-248+695-486+1248\)
\(=\left(1248-248\right)+\left(-486-214\right)+695\)
\(=1000-700+695=300+695=965\)
5: \(\left(-46+2198\right)-\left(-2023-146+198\right)\)
\(=-46+2198+2023+146-198\)
\(=\left(-46+146\right)+\left(2198-198\right)+2023\)
\(=2000+100+2023=2100+2023=4123\)
6: \(\left(-416+25\right)-\left(-1416+17-475\right)\)
\(=-416+25+1416-17+475\)
\(=\left(1416-416\right)+\left(475+25\right)-17\)
\(=1000+500-17=1500-17=1483\)
7: \(\left(-253+1976-41\right)-\left(447+976-241\right)\)
\(=-253+1976-41-447-976+241\)
\(=\left(-253-447\right)+\left(1976-976\right)+\left(241-41\right)\)
\(=-700+1000+200=500\)
8: \(-\left(-195+24-687\right)+\left(424-6195\right)\)
\(=195-24+687+424-6195\)
\(=\left(195-6195\right)+\left(424-24\right)+687\)
\(=-6000+400+687=-6000+1087=-4913\)
9: \(-\left(-241+95-148\right)-\left(6241+305\right)\)
\(=241-95+148-6241-305\)
\(=\left(241-6241\right)+\left(-95-305\right)+148\)
=-6000-400+148
=-6400+148=-6252
\(3-\left(\frac{1}{6}-x\right)\cdot\frac{2}{3}=\frac{2}{3}\)
\(3-\left(\frac{1}{6}-x\right)=\frac{\frac{2}{3}}{\frac{2}{3}}\)
\(3-\left(\frac{1}{6}-x\right)=1\)
\(\frac{1}{6}-x=3-1=2\)
\(x=\frac{1}{6}-2=-\frac{11}{6}\)
\(3-\left(\frac{1}{6}-x\right).\frac{2}{3}=\frac{2}{3}\)
\(\left(\frac{1}{6}-x\right).\frac{2}{3}=3-\frac{2}{3}\)
\(\left(\frac{1}{6}-x\right).\frac{2}{3}=\frac{9}{3}-\frac{2}{3}\)
\(\left(\frac{1}{6}-x\right).\frac{2}{3}=\frac{7}{3}\)
\(\frac{1}{6}-x=\frac{7}{3}:\frac{2}{3}\)
\(\frac{1}{6}-x=\frac{7}{3}:\frac{3}{2}\)
\(\frac{1}{6}-x=\frac{7}{2}\)
\(x=\frac{1}{6}-\frac{7}{2}\)
\(x=\frac{1}{6}-\frac{21}{6}\)
\(x=\frac{-20}{6}=\frac{-10}{3}\)
15B
16A
1. does => doesn't
2. isn't => doesn't
3. go => going
4. spending => spend
Có:
\(\dfrac{3}{16}.\dfrac{12}{11}+\dfrac{3}{16}.\dfrac{7}{11}-\dfrac{3}{16}.\dfrac{8}{11}\)
\(=\dfrac{3}{16}.\left(\dfrac{12}{11}+\dfrac{7}{11}-\dfrac{8}{11}\right)\) (Áp dụng tính chất phân phối)
\(=\dfrac{3}{16}.\left(\dfrac{11}{11}\right)=\dfrac{3}{16}.1=\dfrac{3}{16}\) (đpcm)
Chúc bạn học tốt!![]()
Thanks:3


ok
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