Bài 1: Tìm x
a) \(\left(x-2\right)^4=256\)
b) \(\frac{x^4}{256}=81\)
c) \(125\left(x+\frac{4}{5}\right)^3=729\)
e) \(7^x+2+7x=50\)
f) \(9.13^{x-1}+\frac{4}{169}.13^{x+1}=2197\)
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Bài 1: Tìm x
a) \(\left(x-2\right)^4=256\)
b) \(\frac{x^4}{256}=81\)
c) \(125\left(x+\frac{4}{5}\right)^3=729\)
e) \(7^x+2+7x=50\)
f) \(9.13^{x-1}+\frac{4}{169}.13^{x+1}=2197\)
a)(x-2)^4=4^4
=(x-2)=4 sr x=4+2
sr x=6
xin lỗi nha mình chỉ biết làm bài a thôi mong cậu thông cảm và kb với mình nhé
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Mình biết bài nào làm bài đó thôi nhé
a) (x-2)4 = 256
=> x-2 = 4
x = 4+2
x = 6
b) \(\frac{x^4}{256}=81\)
\(\Rightarrow\frac{x^4}{4^4}=3^4\)
Từ đây có thể làm theo 2 cách khác nhau
C1 : \(\frac{x^4}{4^4}=81\)
\(\Rightarrow\left(\frac{x}{4}\right)^4=81\)
\(\Rightarrow\frac{x}{4}=3\)
x = 3.4
x = 12
C2 : \(\frac{x^4}{4^4}=3^4\)
=> x4 = 34.44
x4 = (3.4)4
x4 = 124
<=> x = 4
c) \(125.\left(x+\frac{4}{5}\right)^3=729\)
\(\left(x+\frac{4}{5}\right)^3=729:125\)
\(\left(x+\frac{4}{5}\right)^3=5,832\)
\(\Rightarrow x+\frac{4}{5}=1,8=\frac{9}{5}\)
\(x=\frac{9}{5}-\frac{4}{5}\)
\(x=\frac{5}{5}=1\)
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a)\(27^x:3^x=9\)
b)\(\frac{125}{5^x}=25\)
c)\(\frac{-243}{\left(-3\right)}x=-245\)
d)\(\left(\frac{1}{3}\right)x=\frac{1}{81}\)
e)\(\frac{-512}{343}=\left(\frac{-8}{7}\right)^x\)
g)\(\left(\frac{-3}{4}\right)^x=\frac{81}{256}\)
a) x=1
b) x=1
c) x= -(245/81)
d) x= 1/27
e) x=3
g) x=4
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Tìm x, biết
a, \(\left(\frac{12}{21}\right)^x=\left(\frac{3}{5}\right)^2-\left(-\frac{3}{5}\right)^4\)
b, \(\left(-\frac{3}{4}\right)^{3x-1}=\frac{256}{81}\)
Help me!!!
1) giải phương trình: a) left(2x+3right)left(frac{3x+8}{2-7x}+1right)left(x+5right)left(frac{3x+8}{2-7x}+1right)b) frac{7x+10}{x+1}left(x^2-x-2right)-frac{7x+10}{x+1}left(2x^2-3x-5right)0c) frac{2x+5}{x+3}+1frac{4}{x^2+2x-3}-frac{3x-1}{1-x}d) frac{13}{2x^2+x-21}+frac{1}{2x+7}+frac{6}{9-x^2}0e) frac{x-49}{50}+frac{x-50}{49}frac{49}{x-50}+frac{50}{x-49}f) frac{1+frac{x}{x+3}}{1-frac{x}{x+3}}3
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1) giải phương trình:
a) \(\left(2x+3\right)\left(\frac{3x+8}{2-7x}+1\right)=\left(x+5\right)\left(\frac{3x+8}{2-7x}+1\right)\)
b) \(\frac{7x+10}{x+1}\left(x^2-x-2\right)-\frac{7x+10}{x+1}\left(2x^2-3x-5\right)=0\)
c) \(\frac{2x+5}{x+3}+1=\frac{4}{x^2+2x-3}-\frac{3x-1}{1-x}\)
d) \(\frac{13}{2x^2+x-21}+\frac{1}{2x+7}+\frac{6}{9-x^2}=0\)
e) \(\frac{x-49}{50}+\frac{x-50}{49}=\frac{49}{x-50}+\frac{50}{x-49}\)
f) \(\frac{1+\frac{x}{x+3}}{1-\frac{x}{x+3}}=3\)
Tìm x, biết:
a) \(\left(\frac{-3}{4}\right)^{3x-1}=\frac{-27}{64}\)
b) \(\left(\frac{4}{5}\right)^{2x+5}=\frac{256}{265}\)
c) \(\frac{\left(x+3\right)^5}{\left(x+3\right)^2}=\frac{64}{27}\)
d) \(\left(x-\frac{2}{15}\right)^3=\frac{8}{125}\)
a) \(\left(-\frac{3}{4}\right)^{3x-1}=\frac{-27}{64}\)
\(\Leftrightarrow\left(-\frac{3}{4}\right)^{3x-1}=\left(-\frac{3}{4}\right)^3\)
\(\Leftrightarrow3x-1=3\)
\(\Leftrightarrow3x=4\)
\(\Leftrightarrow x=\frac{4}{3}\)
b) Đề sai ! Sửa :
\(\left(\frac{4}{5}\right)^{2x+5}=\frac{256}{625}\)
\(\Leftrightarrow\left(\frac{4}{5}\right)^{2x+5}=\left(\frac{4}{5}\right)^4\)
\(\Leftrightarrow2x+5=4\)
\(\Leftrightarrow2x=-1\)
\(\Leftrightarrow x=-\frac{1}{2}\)
c) \(\frac{\left(x+3\right)^5}{\left(x+5\right)^2}=\frac{64}{27}\)
\(\Leftrightarrow\left(x+3\right)^3=\left(\frac{4}{3}\right)^3\)
\(\Leftrightarrow x+3=\frac{4}{3}\)
\(\Leftrightarrow x=-\frac{5}{3}\)
d) \(\left(x-\frac{2}{15}\right)^3=\frac{8}{125}\)
\(\Leftrightarrow\left(x-\frac{2}{15}\right)^3=\left(\frac{2}{15}\right)^3\)
\(\Leftrightarrow x-\frac{2}{15}=\frac{2}{15}\)
\(\Leftrightarrow x=\frac{4}{15}\)
Tìm x:
a)\(5^x.\left(5^3\right)^2=625\)
b)\(\left(\frac{12}{25}\right)^x=\left(\frac{5}{3}\right)^{-2}-\left(-\frac{3}{5}\right)^4\)
c)\(\left(-\frac{3}{4}\right)^{3x-1}=\frac{256}{81}\)
d)\(172.x^2-7^9:98^3=2^{-3}\)
1) Giải các pt sau:
a) frac{x-3}{5}6-frac{1-2x}{3}
b) frac{3x-2}{6}-5frac{3-2left(x+7right)}{4}
c) frac{x+8}{6}-frac{2x-5}{5}frac{x-1}{3}-x+7
d) frac{7x}{8}-5left(x-9right)frac{2x+1,5}{6}
e) frac{5left(x-1right)+2}{6}-frac{7x-1}{4}frac{2left(2x+1right)}{7}-5
f) frac{x+1}{3}+frac{3left(2x+1right)}{4}frac{2x+3left(x+1right)}{6}+frac{7+12x}{12}
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1) Giải các pt sau:
a) \(\frac{x-3}{5}=6-\frac{1-2x}{3}\)
b) \(\frac{3x-2}{6}-5=\frac{3-2\left(x+7\right)}{4}\)
c) \(\frac{x+8}{6}-\frac{2x-5}{5}=\frac{x-1}{3}-x+7\)
d) \(\frac{7x}{8}-5\left(x-9\right)=\frac{2x+1,5}{6}\)
e) \(\frac{5\left(x-1\right)+2}{6}-\frac{7x-1}{4}=\frac{2\left(2x+1\right)}{7}-5\)
f) \(\frac{x+1}{3}+\frac{3\left(2x+1\right)}{4}=\frac{2x+3\left(x+1\right)}{6}+\frac{7+12x}{12}\)
a, \(\frac{x-3}{5}\) = 6 - \(\frac{1-2x}{3}\)
⇔ 3(x - 3) = 90 - 5(1 - 2x)
⇔ 3x - 9 = 90 - 5 + 10x
⇔ 3x - 10x = 90 - 5 + 9
⇔ -7x = 94
⇔ x = \(\frac{-94}{7}\)
S = { \(\frac{-94}{7}\) }
b, \(\frac{3x-2}{6}\) - 5 = \(\frac{3-2\left(x+7\right)}{4}\)
⇔ 2(3x - 2) - 60 = 9 - 6(x + 7)
⇔ 6x - 4 - 60 = 9 - 6x - 42
⇔ 6x + 6x = 9 - 42 + 60 + 4
⇔ 12x = 31
⇔ x = \(\frac{31}{12}\)
S = { \(\frac{31}{12}\) }
c, \(\frac{x+8}{6}\) - \(\frac{2x-5}{5}\) = \(\frac{x+1}{3}\) - x + 7
⇔ 5(x+ 8) - 6(2x - 5) = 10(x+1) - 30x+210
⇔ 5x+ 40 - 12x+ 30 = 10x+ 10 - 30x+210
⇔ 5x - 12x - 10x+ 30x = 10+ 210 - 30- 40
⇔ 13x = 150
⇔ x = \(\frac{150}{13}\)
S = { \(\frac{150}{13}\) }
d, \(\frac{7x}{8}\) - 5(x - 9) = \(\frac{2x+1,5}{6}\)
⇔ 21x - 120(x - 9) = 4(2x + 1,5)
⇔ 21x - 120x + 1080 = 8x + 6
⇔ 21x - 120x - 8x = 6 - 1080
⇔ -107x = -1074
⇔ x = \(\frac{1074}{107}\)
S = { \(\frac{1074}{107}\) }
e, \(\frac{5\left(x-1\right)+2}{6}\) - \(\frac{7x-1}{4}\) = \(\frac{2\left(2x+1\right)}{7}\) - 5
⇔ 140(x-1)+56 - 42(7x-1) = 48(2x+1)-840
⇔ 140x -140+56 -294x+42= 96x+48 -840
⇔ 140x -294x -96x = 48 -840 -42 -56+140
⇔ -250x = -750
⇔ x = 3
S = { 3 }
f, \(\frac{x+1}{3}\) + \(\frac{3\left(2x+1\right)}{4}\) = \(\frac{2x+3\left(x+1\right)}{6}\) + \(\frac{7+12x}{12}\)
⇔ 4(x+1)+9(2x+1) = 4x+6(x+1)+7+12x
⇔ 4x+4+18x+9 = 4x+6x+6+7+12x
⇔ 4x+18x - 4x - 6x - 12x = 6+7- 9 - 4
⇔ 0x = 0
S = R
Chúc bạn học tốt !
bài 1: Tìm x,y biết rằng: x+(-frac{31}{12})^2left(frac{49}{12}right)^2-xy^2 bài 2: tìm x biết:a.5^x.left(5^3right)^2625 b.left(frac{12}{25}right)^xleft(frac{5}{3}right)^{-2}-left(-frac{3}{5}right)^4 c.left(-frac{3}{4}right)^{3x-1}frac{256}{81} d.172x^2-7^9:98^32^{-3}Bài 3: Tìm x varepsilonN biết:a.8 2^xle2^9times2^{-5} b.27 81^3:3^x 243 left(frac{2}{5}right)^xleft(frac{5}{2}right)^{-3}timesleft(-frac{2}{5}right)^2c.
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bài 1: Tìm x,y biết rằng:
\(x+(-\frac{31}{12})^2=\left(\frac{49}{12}\right)^2-x=y^2\)
bài 2: tìm x biết:
a.\(5^x.\left(5^3\right)^2=625\) b.\(\left(\frac{12}{25}\right)^x=\left(\frac{5}{3}\right)^{-2}-\left(-\frac{3}{5}\right)^4\) c.\(\left(-\frac{3}{4}\right)^{3x-1}=\frac{256}{81}\)
d.\(172x^2-7^9:98^3=2^{-3}\)
Bài 3: Tìm x \(\varepsilon\)N biết:
a.\(8< 2^x\le2^9\times2^{-5}\) b.\(27< 81^3:3^x< 243\) \(\left(\frac{2}{5}\right)^x>\left(\frac{5}{2}\right)^{-3}\times\left(-\frac{2}{5}\right)^2\)c.
Bài 1:
Ta có: \(x+\left(-\frac{31}{12}\right)^2=\left(\frac{49}{12}\right)^2-x\)
\(\Leftrightarrow2x=\frac{1440}{144}=10\)
\(\Rightarrow x=5\)
Khi đó: \(y^2=\left(\frac{49}{12}\right)^2-5=\frac{1681}{144}\)
=> \(\hept{\begin{cases}y=\frac{41}{12}\\y=-\frac{41}{12}\end{cases}}\)
Bài 1: Thực hiện phép tính:a, 3frac{1}{2}-frac{1}{2}.left(-4,25-frac{3}{4}right)^2:frac{5}{4}b, frac{3}{7}.1frac{1}{2}+frac{3}{7}.0,5-frac{3}{7}.9c, frac{125^{2016}.8^{2017}}{50^{2017}.20^{2018}}d, frac{4^{2002}.9^{1001}}{16^{1001}.3^{2003}}e, sqrt{25-16}-left|-3,7+0,7right|Bài 2: Tìm xa, frac{1}{3}x+frac{4}{5}3frac{4}{5}b, left|x+frac{3}{4}right|-2,251frac{3}{4}c, left(-x+frac{2}{5}right)^4frac{1}{16}d, left(frac{2}{5}right)^{3x}:left(frac{4}{3}right)^{21}left(frac{6}{20}right)^{21}e, frac{-x}{...
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Bài 1: Thực hiện phép tính:
a, \(3\frac{1}{2}-\frac{1}{2}.\left(-4,25-\frac{3}{4}\right)^2:\frac{5}{4}\)
b, \(\frac{3}{7}.1\frac{1}{2}+\frac{3}{7}.0,5-\frac{3}{7}.9\)
c, \(\frac{125^{2016}.8^{2017}}{50^{2017}.20^{2018}}\)
d, \(\frac{4^{2002}.9^{1001}}{16^{1001}.3^{2003}}\)
e, \(\sqrt{25-16}-\left|-3,7+0,7\right|\)
Bài 2: Tìm x
a, \(\frac{1}{3}x+\frac{4}{5}=3\frac{4}{5}\)
b, \(\left|x+\frac{3}{4}\right|-2,25=1\frac{3}{4}\)
c, \(\left(-x+\frac{2}{5}\right)^4=\frac{1}{16}\)
d, \(\left(\frac{2}{5}\right)^{3x}:\left(\frac{4}{3}\right)^{21}=\left(\frac{6}{20}\right)^{21}\)
e, \(\frac{-x}{\frac{3}{5}}=\frac{\frac{27}{5}}{-x}\)
g, \(x:1\frac{1}{2}=-2,5:2\frac{1}{5}\)
\(3\frac{1}{2}-\frac{1}{2}.\left(-4,25-\frac{3}{4}\right)^2:\frac{5}{4}\)
\(=\frac{7}{2}-\frac{1}{2}.\left(-4,25-0,75\right)^2:\frac{5}{4}\)
\(=\frac{7}{2}-\frac{1}{2}.\left(-5\right)^2:\frac{5}{4}\)
\(=\frac{7}{2}-\frac{1}{2}.5.\frac{4}{5}\)
\(=\frac{7}{2}-2\)
\(=\frac{7}{2}-\frac{4}{2}\)
\(=\frac{3}{2}\)
\(\frac{3}{7}.1\frac{1}{2}+\frac{3}{7}.0,5-\frac{3}{7}.9\)
\(=\frac{3}{7}.\left(\frac{3}{2}+\frac{1}{2}-9\right)\)
\(=\frac{3}{7}.\left(2-9\right)\)
\(=\frac{3}{7}.\left(-7\right)\)
\(=-3\)
\(\frac{125^{2016}.8^{2017}}{50^{2017}.20^{2018}}=\frac{\left(5^3\right)^{2016}.\left(2^3\right)^{2017}}{\left(5^2\right)^{2017}.2^{2017}.\left(2^2\right)^{2018}.5^{2018}}=\frac{\left(5^3\right)^{2016}.\left(2^3\right)^{2017}}{\left(5^3\right)^{2017}.\left(2^3\right)^{2017}.2.5}=\frac{1}{5^4.2}=\frac{1}{1250}\)( tính nhẩm, ko chắc đúng )
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1
a) \(3\frac{1}{2}-\frac{1}{2}\cdot\left(-4,25-\frac{3}{4}\right)^2\) : \(\frac{5}{4}\)
= \(3\cdot25:\frac{5}{4}\)
= \(3\cdot\left(25:\frac{5}{4}\right)\)
=\(3\cdot20\)
=60
b)=\(\frac{3}{7}\cdot\left(1\frac{1}{2}+0,5-9\right)\)
=\(\frac{3}{7}\cdot\left(-7\right)\)
=\(-3\)
c) =
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