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a: \(A=\dfrac{4^{15}\cdot7^{15}\cdot3^{17}}{4^{32}\cdot3^{16}}=\dfrac{1}{4^{17}}\cdot3\cdot7^{15}=\dfrac{3\cdot7^{15}}{4^{17}}\)
b: \(B=\dfrac{3^{10}+6^2}{5\cdot3^8+20}=\dfrac{3^{10}+3^2\cdot4}{5\left(3^8+4\right)}=\dfrac{3^2\left(3^8+4\right)}{5\left(3^8+4\right)}=\dfrac{9}{5}\)
1)
a) \(\left(-48\right)^3:16^3\)
\(=\left(-48:16\right)^3\)
\(=\left(-3\right)^3\)
\(=-27.\)
b) \(\left(\frac{9}{10}\right)^6:\left(\frac{17}{-20}\right)^6\)
\(=\left(\frac{9}{10}:\frac{17}{-20}\right)^6\)
\(=\left(-\frac{18}{17}\right)^6\)
Chúc em học tốt!
\(\frac{-13^3}{\left(2^3\right)^3}:\frac{\left(-2^5\right)^4}{13^4}\)1.
a, (-48)3:163
= \(\left(\frac{-48}{16}\right)^3\)
= (-3)3
b,\(\left(\frac{9}{10}\right)^6\):\(\left(\frac{17}{-20}\right)^6\)
= \(\left(\frac{9}{10}:\frac{17}{-20}\right)^6\)
=\(\left(\frac{-18}{17}\right)^6\)
c, \(\left(\frac{-13}{8}\right)^3:\left(\frac{-32}{13}\right)^4\)
= \(\frac{-13^3}{\left(2^3\right)^3}:\frac{\left(-2^5\right)^4}{13^4}\)
= \(\frac{-13^3}{2^9}.\frac{-13^4}{2^{20}}\)
=\(\frac{13^7}{2^{29}}\)
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) \(3\frac{1}{2}\cdot\frac{4}{49}-\left[2,\left(4\right)\cdot2\frac{5}{11}\right]:\frac{-42}{53}\)
\(=\frac{7}{2}\cdot\frac{4}{49}-\left[\frac{22}{9}\cdot\frac{27}{11}\right]\cdot\frac{-53}{42}\)
\(=\frac{2}{7}-6\cdot\left(-\frac{53}{42}\right)=\frac{2}{7}-\left(-\frac{53}{7}\right)=\frac{2}{7}+\frac{53}{7}=\frac{55}{7}\)
c) Tìm các số nguyên x,y thỏa mãn
*\(2xy+6x-y=10\)
\(\Leftrightarrow\left(2xy+6x\right)-y-3=10-3=7\)
\(\Leftrightarrow2x\left(y+3\right)-\left(y+3\right)=7\)
\(\Leftrightarrow\left(y+3\right)\left(2x-1\right)=7\)
Lập bảng xét ước nữa là xong.
* \(xy+4x-3y=1\Leftrightarrow\left(xy+4x\right)-3y-12=1-12=-11\)
\(\Leftrightarrow x\left(y+4\right)-\left(3y+12\right)=-11\)
\(\Leftrightarrow x\left(y+4\right)-3\left(y+4\right)=-11\)
\(\Leftrightarrow\left(x-3\right)\left(y+4\right)=-11\)
Lập bảng xét ước nữa là xong.
Mới nhìn vào thấy bài toán hay hay lạ kì.
Thêm một vào bớt một ra
Tức thì bài toán trở nên dễ dàng:
\(\frac{x}{50}-\frac{x-1}{51}=\frac{x+2}{48}-\frac{x-3}{53}\)
\(\Leftrightarrow\frac{x}{50}+1-\frac{x-1}{51}-1=\frac{x+2}{48}+1-\frac{x-3}{53}-1\)
\(\Leftrightarrow\left(\frac{x}{50}+1\right)-\left(\frac{x-1}{51}+1\right)=\left(\frac{x+2}{48}+1\right)-\left(\frac{x-3}{53}+1\right)\)
\(\Leftrightarrow\frac{x+50}{50}-\frac{x+50}{51}=\frac{x+50}{48}-\frac{x+50}{53}\)
\(\Leftrightarrow\frac{x+50}{50}-\frac{x+50}{51}-\frac{x+50}{48}+\frac{x+50}{53}=0\)
\(\Leftrightarrow\left(x+50\right)\left(\frac{1}{50}-\frac{1}{51}-\frac{1}{48}+\frac{1}{53}\right)=0\)
Dễ thấy \(\left(\frac{1}{50}-\frac{1}{51}-\frac{1}{48}+\frac{1}{53}\right)\ne0\)
Do đó x + 50 = 0 hay x = -50
a/ \(5\dfrac{5}{47}+\dfrac{37}{53}+2,7-\dfrac{5}{47}+\dfrac{6}{53}\)
= \(\dfrac{240}{47}-\dfrac{5}{47}+\dfrac{37}{53}+\dfrac{6}{53}+2,7\)
=\(\left(\dfrac{240}{47}-\dfrac{5}{47}\right)+\left(\dfrac{37}{53}+\dfrac{6}{53}\right)+2,7\)
= 5 + \(\dfrac{43}{53}\) + 2,7 = \(\dfrac{4511}{530}\)
b/ \(42\dfrac{1}{6}:\left(-1\dfrac{3}{5}\right)-52\dfrac{1}{6}:\left(-1\dfrac{3}{5}\right)\)
= \(\left(42\dfrac{1}{6}-52\dfrac{1}{6}\right):\left(-1\dfrac{3}{5}\right)\)
= \(-10:\left(-1\dfrac{3}{5}\right)\) =25/4
a)(23)17-248
=251-248
=248.(23-1)
=(248.7)chia hết cho 7
c)=(33)13-(32)18
=339-336
=336.(33-1)
=336.26
=335.3.13.2
=(335.39.2)chia hết cho 39
cho tớ nha thanks
Câu a:
6 - (2 - 6) + 10
= 6 - 2 - 6 + 10
= (10 - 2) + (6 - 6)
= 8+ 0
= 8
Câu b:
(4 - 17 - 53) - (- 53 + 48) + 48
= 4 - 17 - 53 + 53 - 48+ 48
= - (17 - 4) -(53 - 53) - (48 - 48)
= - 13 - 0 - 0
= - 13
= - 13
a 6-(2-6)+10 b(4-17-53)-(-53 +48)+48
=6-2+6+10 =4-17-53- (-53)+ 48 + 48
=6-6+2+10 =48-48+ 53+(-53)
=0+12 =0+ 0
=12 =0
Cô Hoài ơi, giáo viên của mình bảo câu a đáp án là 20 ạ
Câu a:
6 - (2 - 6) + 10
= 6 - 2 - 6 + 10
= (10 - 2) + (6 - 6)
= 8+ 0
= 8
Câu b:
(4 - 17 - 53) - (- 53 + 48) + 48
= 4 - 17 - 53 + 53 - 48+ 48
= - (17 - 4) -(53 - 53) - (48 - 48)
= - 13 - 0 - 0
= - 13
= - 13