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$a) -660\left ( \dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{11} \right )+123.(-38)+62.(-123)\\=-660.\dfrac{17}{66}-4674-7626\\=-10.17-4676-7626\\=-170-4674-7626=-12470\\b) \dfrac{0,375-0,3+\dfrac{3}{11}+\dfrac{3}{12}}{-0,625+0,5-\dfrac{5}{11}-\dfrac{5}{12}}+\dfrac{1,5+1-0,75}{2,5+\dfrac{5}{3}-1,25}\\=\dfrac{\dfrac{3}{8}-\dfrac{3}{10}+\dfrac{3}{11}+\dfrac{3}{12}}{-\dfrac{5}{8}+\dfrac{1}{2}-\dfrac{5}{11}-\dfrac{5}{12}}+\dfrac{1,75}{1,25+\dfrac{5}{3}}\\=\dfrac{\frac{263}{440}}{-\dfrac{263}{264}}+\dfrac{\dfrac{7}{4}}{\dfrac{5}{4}+\dfrac{5}{3}}\\=-\dfrac{\dfrac{263}{440}}{\dfrac{263}{264}}+\dfrac{\dfrac{7}{4}}{\dfrac{35}{12}}\\=-\dfrac{3}{5}+\dfrac{3}{5}=0\\c) \dfrac{8^{10}+4^{10}}{8^{4}+4^{11}}\\=\dfrac{(2.4)^{10}+4^{10}}{2^{12}+2^{22}}\\=\dfrac{2^{10}.4^{10}+4^{10}}{(1+2^{10}).2^{12}}\\=\dfrac{2^{10}.2^{10}.(2^{10}+1)}{(1+1024).2^{12}}\\=\dfrac{2^{10}.(1024+1)}{1025.2^{2}}\\=\dfrac{2^{8}.1025}{1025}=2^{8}\\d) \dfrac{2.5^{22}-9.5^{21}}{25^{10}}:\dfrac{5.(3.7^{15}-19.7^{14})}{7^{16}+3.7^{15}}\\=\dfrac{(2.5-9).5^{21}}{5^{20}}:\dfrac{5(3.7-19).7^{14}}{(7+3).7^{15}}\\=(10-9).5:\frac{5(21-19).7^{14}}{10.7^{15}}\\=1.5:\frac{5.2.7^{14}}{10.7^{15}}\\=5.\dfrac{10.7^{15}}{5.2.7^{14}}\\=5.7=35$
Hãy giúp mọi người biết câu trả lời này thế nào?
Đáp án:
a) `-12470`
b) `0`
c) `256`
d) `35`
Giải thích các bước giải:
a) `-660.(1/2 - 1/3 + 1/11) + 123 . (-38) + 62.(-123)`
`= -660 . 17/66 - 123 . (38+62)`
`= -170 - 123 . 100`
`= -170 -12300 = -12470`
b) `(0,375-0,3+3/11+3/12)/(-0,625+0,5-5/11-5/12)+(1,5+1-0,75)/(2,5+5/3-1,25)`
`= (3(0,125-0,1+1/11+1/12))/(-5(0,125-0,1+1/11+1/12))+(3(0,5+1/3-0,25))/(5(0,5+1/3-0,25)`
`=-3/5+3/5=0`
c) `(8^10+4^10)/(8^4+4^11)`
`=((2^3)^10+(2^2)^10)/((2^3)^4+(2^2)^11)`
`=(2^30+2^20)/(2^12+2^22)`
`=(2^20(2^10+1))/(2^12(1+2^10))`
`=2^8=256`
d) `(2.5^22-9.5^21)/(25^10):(5(3.7^15-19.7^14))/(7^16+3.7^15)`
`=(5^21(2.5-9))/(5^2)^10.(7^15(7+3))/(5[7^14(3.7-19)])`
`=5^21/5^20.(7^15 .10)/(5.7^14 .2`
`=5.(7^15 . 10)/(7^14 .10)`
`=5.7=35`
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