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Bài 1:
29.(85-47)+85.(47-29)
=29.38+85.18
=1102+1530
=2632
BÀI 2
a, 15x = -75
x =( -75) : 15
x = -5
Vậy x= -5
b,-5x+8=-27
-5x = -27 - 8
-5x= -35
x =-35 : -5
x = 7
Vậy x = 7
c,3.(17 + x ) = - 42
17 + x = - 42 : 3
17 + x = -14
x = - 14 - 17
x = -31
Vậy x = - 31
d,-10 -( 2x -16) = 0
2x - 16 = 10-0
2x - 16 = 10
2x = 10 +16
2x = 26
x = 26 : 2
x = 13
Vậy x = 13
e,( mik ko bít làm)
f,( tự làm nghen bạn)
a) \(3^2.x+2^3.x=51\)
\(\Leftrightarrow x\left(3^2+2^3\right)=51\)
\(\Leftrightarrow17x=51\)
\(\Leftrightarrow x=3\)
Vậy
b) \(6^2.2-\left(84-3^2.x\right):7=69\)
\(\Leftrightarrow\left(84-3^2.x\right):7=3\)
\(\Leftrightarrow84-3^2.x=21\)
\(\Leftrightarrow3^2.x=63\)
\(\Leftrightarrow x=7\)
Vậy
1/ a) \(2.3.12.12.3=2.3.2^2.3.2^2.3.3=2^5.3^4\)
b) \(3.5.27.125=3.5.3^3.5^3=3^4.5^4=\left(3.5\right)^4\)
2/ a) \(\left(27^3\right)^4=27^{3.4}=27^{12}\)
Vậy \(\left(27^3\right)^4=27^{12}\)
b) \(5^{36}=\left(5^6\right)^6\) và \(11^{24}=\left(11^4\right)^6\)
Do đó \(5^6=15625\) và \(11^4=14641\)
Vì 15625>14641 nên\(\left(5^6\right)^6>\left(11^4\right)^6hay5^{36}>11^{24}.\)
3/ a) \(x^3=125=>x=5\)
b) \(\left(3x-14\right)^3=2^5.5^2+200\)
\(\left(3x-14\right)^3=1000\)
\(3x-14=10^3\)
\(3x=10^3+14\)
\(3x=1014\)
\(x=\frac{1014}{3}=338\)
c) \(\left(2x-1\right)^4=81\)
\(\left(2x-1\right)^4=3^4\)
\(2x-1=3\)
\(2x=3+1\)
\(x=\frac{4}{2}=2\)
d) \(5x+3^4=2^2.7^2\)
\(5x+3^4=\left(2.7\right)^2=14^2\)
\(5x+81=196\)
\(5x=196-81\)
\(5x=115\)
\(x=\frac{115}{5}=23\)
e) \(4^x=1024=>x=5\).
a/ \(51-(-12+3x)=27\)
\(\Leftrightarrow51+12-27-3x=0\Leftrightarrow36=3x\Leftrightarrow x=\frac{36}{3}=12\)
KL:........
b/ $-x + 21=15+ 2x$
\(\Leftrightarrow2x+x=21-15\Leftrightarrow2x=6\Leftrightarrow x=3\)
KL: ...........
c) $7.(x-9)-5(6-x)=-6+11.x$
\(\Leftrightarrow7x-63-30+5x=-6+11x\Leftrightarrow7x+5x-11x=-6+63+30\Leftrightarrow x=87\)
KL:............
d) $(x-3).(x^2 + 2)=0$
\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\x^2+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x\in\varnothing\end{matrix}\right.\)\(\Leftrightarrow x=3\)
e) $|2x-7|-22=-13$
\(\Leftrightarrow\left|2x-7\right|=9\Leftrightarrow\left[{}\begin{matrix}2x-7=9\\2x-7=-9\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=8\\x=-1\end{matrix}\right.\)
KL: ...........
f) $(2x - 1)^3=-125$
\(\Leftrightarrow\left(2x-1\right)^3=\left(-5\right)^3\Leftrightarrow2x-1=-5\Leftrightarrow x=-2\)
KL: ...........
a) 2x = 16 e) 12x = 144
2x = 24 12x = 122
=> x = 4 => x = 2
b) 2x+1 = 16 các câu còn lại tương tự nhé nhiều quá
2x+1 = 24
x + 1 = 4
=> x = 3
c) 5x+1 = 125
5x+1 = 53
x + 1 = 3
=> x = 2
d) 52x - 1 = 125
52x-1 = 53
2x - 1 = 3
2x = 4
=> x = 2
a)Ta có : 2x = 16
2x = 24
=> x = 4
b) Ta có: 2x+1 = 16
2x+1 = 24
=> x+1 = 4
=> x = 4-1
=> x = 3
Mấy câu sau tương tự vậy đó để hôm khác mình làm tiếp cho bây giờ mình đi ngủ đã buồn ngủ quá hihi ! ^-^
Học tốt nha bạn !
a) \(4^n=4096\Rightarrow4^n=4^6\Rightarrow n=6\)
b) \(5^n=15625\Rightarrow5^n=5^6\Rightarrow n=6\)
c) \(6^{n+3}=216\Rightarrow6^{n+3}=6^3\Rightarrow n+3=3\Rightarrow n=0\)
d) \(x^2=x^3\Rightarrow x^3-x^2=0\Rightarrow x^2\left(x-1\right)=0\Rightarrow\left[{}\begin{matrix}x=0\\x-1=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)
e) \(3^{x-1}=27\Rightarrow3^{x-1}=3^3\Rightarrow x-1=3\Rightarrow x=4\)
f) \(3^{x+1}=9\Rightarrow3^{x+1}=3^2\Rightarrow x+1=2\Rightarrow x=1\)
g) \(6^{x+1}=36\Rightarrow6^{x+1}=6^2\Rightarrow x+1=2\Rightarrow x=1\)
h) \(3^{2x+1}=27\Rightarrow3^{2x+1}=3^3\Rightarrow2x+1=3\Rightarrow2x=2\Rightarrow x=1\)
i) \(x^{50}=x\Rightarrow x^{50}-x=0\Rightarrow x\left(x^{49}-1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x^{49}-1=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=0\\x^{49}=1=1^{49}\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)
4n = 4096
4n = 212
n = 12
5n = 15625
5n = 56
n = 6
6n+3 = 216
6n+3 = 23.33
6n+3 = 63
n + 3 = 3
\(\left(x+1\right)^3=27\)
\(\left(x+1\right)^3=3^3\)
\(\Rightarrow x+1=3\)
\(x=2\)
\(\left(x+1\right)^3=27\)
\(< =>\left(x+1\right)^3=3.3.3=3^3\)
\(< =>x+1=3< =>x=3-1=2\)
\(\left(2x+3\right)^3=9.81\)
\(< =>\left(2x+3\right)^3=9.9.9\)
\(< =>\left(2x+3\right)^3=9^3\)
\(< =>2x+3=9< =>2x=6\)
\(< =>x=\frac{6}{2}=3\)
1) \(\left(-27\right).\left(-28+128\right)=-27.100=-2700\)
2a)\(\left(x-3\right)\left(2x+6\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\2x+6=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)
b) \(\left(2x-1\right)^2=81\)
\(\sqrt{\left(2x-1\right)^2}=9\)
\(\left|2x-1\right|=9\)
\(\left[{}\begin{matrix}2x-1=9\\2x-1=-9\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-4\end{matrix}\right.\)
c) \(\left(2m+5\right)^3=-27\)
\(\sqrt[3]{\left(2m+5\right)^3}=-3\)
\(2m+5=-3\)
\(m=-4\)
d) \(\left(3x-2\right)^3=64\)
tương tự câu c