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- \(0 , 6 - 75 \% = \frac{3}{5} - \frac{3}{4} = - \frac{3}{20}\).
- \(\frac{1}{5} - 1 \frac{3}{4} = \frac{1}{5} - \frac{7}{4} = - \frac{31}{20}\).
- \(\left(\right. - 3 / 20 \left.\right) : \left(\right. - 31 / 20 \left.\right) = 3 / 31\)=0,0968
Câu a:
A = (-5/11).7/15.(-11/-5).(-30)
A = [(-5/11).(11/-5)].[7/15.(-30)]
A = 1 .[-14]
A = -14
a) \(10,\left(3\right)+0,\left(4\right)-8,\left(6\right)\)
\(=\frac{31}{3}+\frac{4}{9}-\frac{26}{3}\)
\(=\left(\frac{31}{3}-\frac{26}{3}\right)+\frac{4}{9}=\frac{5}{3}+\frac{4}{9}=\frac{15}{9}+\frac{4}{9}=\frac{19}{9}\)
b) \(\left[12,\left(1\right)-2,3\left(6\right)\right]:4,\left(21\right)\)
\(=\left[\frac{109}{9}-\frac{71}{30}\right]:\frac{139}{33}\)
\(=-\frac{52}{45}:\frac{139}{33}=-\frac{52}{45}\cdot\frac{33}{139}=-\frac{572}{2085}\)(số xấu quá)
c) \(3\frac{1}{2}\cdot\frac{4}{49}-\left[2,\left(4\right)\cdot2\frac{5}{11}\right]:\frac{-42}{53}\)
\(=\frac{7}{2}\cdot\frac{4}{49}-\left[\frac{22}{9}\cdot\frac{27}{11}\right]\cdot\frac{-53}{42}\)
\(=\frac{2}{7}-6\cdot\left(-\frac{53}{42}\right)=\frac{2}{7}-\left(-\frac{53}{7}\right)=\frac{2}{7}+\frac{53}{7}=\frac{55}{7}\)
a) \(\frac{3^{17}.81^{11}}{27^{10}.9^{15}}=\frac{3^{17}.\left(3^4\right)^{11}}{\left(3^3\right)^{10}.\left(3^2\right)^{15}}=\frac{3^{17}.3^{44}}{3^{30}.3^{30}}=\frac{3^{61}}{3^{60}}=3\)
b) \(\frac{9^2.2^{11}}{16^2.6^3}=\frac{\left(3^2\right)^2.2^{11}}{\left(2^4\right)^2.2^3.3^3}=\frac{3^4.2^{11}}{2^8.2^3.3^3}=\frac{3^4.2^{11}}{2^{11}.3^3}=3\)
c) \(\frac{2^{10}.3^{31}+2^{40}.3^6}{2^{11}.3^{31}+2^{41}.3^6}=\frac{2^{10}.3^{31}+2^{40}.3^6}{2.\left(2^{10}.3^{31}+2^{40}.3^6\right)}=\frac{1}{2}\)
c) \(\frac{0,375-0,3+\frac{3}{11}+\frac{3}{12}}{0,625-0,5+\frac{5}{11}+\frac{5}{12}}=\frac{3\left(0,125-0,1+\frac{1}{11}+\frac{1}{12}\right)}{5\left(0,123-0,1+\frac{1}{11}+\frac{1}{12}\right)}=\frac{3}{5}\)
a: \(\dfrac{-6}{11}\cdot\dfrac{-11}{6}\cdot\dfrac{7}{10}\cdot\left(-20\right)=-7\cdot2=-14\)
b: \(=\dfrac{-3}{2}\cdot\dfrac{4}{3}\cdot\dfrac{-9}{2}=2\cdot\dfrac{-9}{2}=-9\)
−x2+7x+120=22 \(- x^{2} + 7 x + 98 = 0\) \(x^{2} - 7 x - 98 = 0\)
Phân tích:
\(\left(\right. x - 14 \left.\right) \left(\right. x + 7 \left.\right) = 0\)
5. Kết luận
\(\boxed{x = 14 \text{ho}ặ\text{c} x = - 7}\)
👉
Ta có; (x-3)+(x-2)+(x-1)+...+10+11=11
=>(x-3)+(x-2)+...+10=0
=>x-3+10=0
=>x+7=0
=>x=-7