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Cho mình câu chả lời sớm nhất vào 4h30 chiều ngày 28/9/2021
a) (3x +5)3 =121.(-11)
(3x +5)3 = -113
3x + 5 = -11
3x = -11 - 5
x = \(-\frac{16}{3}\)
b) 3.|2x +1| - 10= |-11|
3.|2x+1| = 11 + 10
|2x+1| = 7
\(\Rightarrow\orbr{\begin{cases}2x+1=7\\2x+1=-7\end{cases}\Rightarrow\orbr{\begin{cases}x=3\\x=-4\end{cases}}}\)
c) 100-(x -5)2 = (-6)2
(x-5)2 = 82
x-5 = 8
x = 13
\(\left(3x+5\right)^3=121\left(-11\right)\)
\(\Rightarrow\left(3x+5\right)^3=-1331=\left(-11\right)^3\)
\(\Rightarrow3x+5=-11\)
\(\Rightarrow3x=-16\)
\(\Rightarrow x=-\frac{16}{3}\)
\(3\left|2x+1\right|-10=\left|-11\right|\)
\(\Rightarrow\left|2x+1\right|=7\)
\(\Leftrightarrow\orbr{\begin{cases}2x+1=7\\2x+1=-7\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=3\\x=-4\end{cases}}\)
\(100-\left(x-5\right)^2=\left(-6\right)^2\)
\(\Rightarrow\left(x-5\right)^2=64=\left(\pm8\right)^2\)
\(\Leftrightarrow\orbr{\begin{cases}x-5=8\\x-5=-8\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=13\\x=-3\end{cases}}\)
a) \(10-2\left(4-3x\right)=-4\)
\(2\left(4-3x\right)=10-\left(-4\right)\)
\(2\left(4-3x\right)=14\)
\(4-3x=\dfrac{14}{2}\)
\(4-3x=7\)
\(3x=4-7\)
\(3x=-3\)
\(x=-1\)
b) \(-12+3\left(-x+7\right)=-18\)
\(3\left(-x+7\right)=-18+12\)
\(3\left(-x+7\right)=-6\)
\(-x+7=-2\)
\(-x=-2-7\)
\(-x=-9\)
\(x=9\)
c) \(24:\left(3x-2\right)=-3\)
\(3x-2=24:\left(-3\right)\)
\(3x-2=-8\)
\(3x=-8+2\)
\(3x=-6\)
\(x=-2\)
d) \(-45:5\left(-3-2x\right)=3\)
\(5\left(-3-2x\right)=-45:3\)
\(5\left(-3-2x\right)=-15\)
\(-3-2x=-15:5\)
\(-3-2x=-3\)
\(-2x=-3+3\)
\(-2x=0\)
\(x=0\)
`#3107`
b)
`2.3^x = 162`
`\Rightarrow 3^x = 162 \div 2`
`\Rightarrow 3^x = 81`
`\Rightarrow 3^x = 3^4`
`\Rightarrow x = 4`
Vậy, `x = 4`
c)
`(2x - 15)^5 = (2 - 15)^3`
\(\Rightarrow \)`(2x - 15)^5 - (2x - 15)^3 = 0`
\(\Rightarrow \)`(2x - 15)^3 . [ (2x - 15)^2 - 1] = 0`
\(\Rightarrow\left[{}\begin{matrix}\left(2x-15\right)^3=0\\\left(2x-15\right)^2-1=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}2x-15=0\\\left(2x-15\right)^2=1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}2x=15\\\left(2x-15\right)^2=\left(\pm1\right)^2\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{15}{2}\\2x-15=1\\2x-15=-1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{15}{2}\\2x=16\\2x=-14\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{15}{2}\\x=8\\x=-7\end{matrix}\right.\)
Vậy, `x \in`\(\left\{-7;8;\dfrac{15}{2}\right\}.\)
`d)`
\(3^{x+2}-5.3^x=?\) Bạn ghi tiếp đề nhé!
`e)`
\(7\cdot4^{x-1}+4^{x-1}=23?\)
\(4^{x-1}\cdot\left(7+1\right)=23\\ \Rightarrow4^{x-1}\cdot8=23\\ \Rightarrow4^{x-1}=\dfrac{23}{8}\)
Bạn xem lại đề!
`f)`
\(2\cdot2^{2x}+4^3\cdot4^x=1056\)
\(\Rightarrow2\cdot2^{2x}+\left(2^2\right)^3\cdot\left(2^2\right)^x=1056\\ \Rightarrow2\cdot2^{2x}+2^6\cdot2^{2x}=1056\\ \Rightarrow2^{2x}\cdot\left(2+2^6\right)=1056\\ \Rightarrow2^{2x}\cdot66=1056\\ \Rightarrow2^{2x}=1056\div66\\ \Rightarrow2^{2x}=16\\ \Rightarrow2^{2x}=2^4\\ \Rightarrow2x=4\\ \Rightarrow x=2\)
Vậy, `x = 2`
_____
\(10 -{[(x \div 3+17) \div 10+3.2^4] \div 10}=5\)
\(\Rightarrow\left[\left(x\div3+17\right)\div10+48\right]\div10=10-5\)
\(\Rightarrow\left[\left(x\div3+17\right)\div10+48\right]\div10=5\)
\(\Rightarrow\left(x\div3+17\right)\div10+48=50\)
\(\Rightarrow\left(x\div3+17\right)\div10=2\)
\(\Rightarrow x\div3+17=20\)
\(\Rightarrow x\div3=3\\ \Rightarrow x=9\)
Vậy, `x = 9.`
a) \(\dfrac{2}{3}x-\dfrac{1}{2}=\dfrac{1}{10}\)
\(\dfrac{2}{3}x=\dfrac{1}{10}+\dfrac{1}{2}=\dfrac{3}{5}\)
\(x=\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{9}{10}\)
b) \(\dfrac{39}{7}:x=13\)
\(x=\dfrac{\dfrac{39}{7}}{13}=\dfrac{3}{7}\)
c) \(\left(\dfrac{14}{5}x-50\right):\dfrac{2}{3}=51\)
\(\dfrac{14}{5}x-50=51\cdot\dfrac{2}{3}=34\)
\(\dfrac{14}{5}x=34+50=84\)
\(x=\dfrac{84}{\dfrac{14}{5}}=30\)
d) \(\left(x+\dfrac{1}{2}\right)\left(\dfrac{2}{3}-2x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\\dfrac{2}{3}-2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)
e) \(\dfrac{2}{3}x-\dfrac{1}{2}x=\dfrac{5}{12}\)
\(\dfrac{1}{6}x=\dfrac{5}{12}\)
\(x=\dfrac{5}{12}:\dfrac{1}{6}=\dfrac{5}{2}\)
g) \(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\dfrac{11}{5}-\dfrac{3}{7}=-2\)
\(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\cdot\dfrac{11}{5}=-2+\dfrac{3}{7}=-\dfrac{11}{7}\)
\(x\cdot\dfrac{44}{7}+\dfrac{3}{7}=-\dfrac{11}{7}:\dfrac{11}{5}=-\dfrac{5}{7}\)
\(\dfrac{44}{7}x=-\dfrac{5}{7}-\dfrac{3}{7}=-\dfrac{8}{7}\)
\(x=-\dfrac{8}{7}:\dfrac{44}{7}=-\dfrac{2}{11}\)
h) \(\dfrac{13}{4}x+\left(-\dfrac{7}{6}\right)x-\dfrac{5}{3}=\dfrac{5}{12}\)
\(\dfrac{25}{12}x-\dfrac{5}{3}=\dfrac{5}{12}\)
\(\dfrac{25}{12}x=\dfrac{5}{12}+\dfrac{5}{3}=\dfrac{25}{12}\)
\(x=1\)
Mỏi tay woa bn làm nốt nha!!
c) 10 . {[(x : 3 + 17) : 10 + 3 . 2^2] : 10} = 5
[(x : 3 + 17) : 10 + 3 . 4] : 10 = 5 : 10
[(x : 3 + 17) : 10 + 12] : 10 = 1/2
(x : 3 + 17) : 10 + 12 = 1/2 . 10
(x : 3 + 17) : 10 + 12 = 5
(x : 3 + 17) : 10 = 5 - 12
(x : 3 + 17) : 10 = -7
=> x : 3 + 17 = -7 . 10
x : 3 + 17 = -70
x : 3 = -70 - 17
x : 3 = -87
x = -87 . 3
x = -261
a ) \(\left(4x+5\right):3-121:1=4\)
\(\Leftrightarrow\left(4x+5\right):3-11=4\)
\(\Leftrightarrow\left(4x+5\right):3=15\)
\(\Leftrightarrow\left(4x+5\right)=45\)
\(\Leftrightarrow4x=40\)
\(\Leftrightarrow x=10\)
Tiếp tịch như z là đc