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\(a,[\left(8.x-12\right):4].3^3.3=3^6.6\)
\(\left(8x-12\right):4=54\)
\(8x-12=216\)
\(8x=228\)
\(x=28,5\)
\(b,41-2^{x+1}=9\)
\(2^{x+1}=41-9\)
\(2^{x+1}=32\)
\(2^{x+1}=2^5\)
\(\Rightarrow x+1=5\)
\(\Rightarrow x=4\)
3 mũ 2x-4 0x mũ 0 bằng 8
3 mũ 2x-4 -1 bằng 8
3 mũ 2x-4 bằng 9
3 mũ 2x-4 bằng 3 mũ 3
suy ra 2x-4 bằng 3
suy ra 2x bằng 7
suy ra x bằng 3,5
65-4x+2=20140
=> 65-4x+2=1
=> 4x+2=64
4 x+2=43
x+2 = 3
x = -1
a: \(\Leftrightarrow\left[\left(3x+14\right):4-3\right]:2=1\)
=>(3x+14):4-3=2
=>(3x+14):4=5
=>3x+14=20
=>3x=6
hay x=2
b: \(\Leftrightarrow\left[\left(x:4+17\right):10+3\cdot16\right]:10=5\)
\(\Leftrightarrow\left(x:4+17\right):10=50-48=2\)
=>x:4+17=20
=>x:4=3
hay x=12
c: \(\Leftrightarrow2\cdot15^2+\left[2\cdot125-\left(2x+4\right)\cdot5\right]:19=453\)
\(\Leftrightarrow250-\left(2x+4\right)\cdot5=\left(453-450\right)\cdot19=57\)
=>5(2x+4)=197
=>2x+4=197/5
=>2x=177/5
hay x=177/10
d: \(\Leftrightarrow\left(19x+50\right):14=5^2-4^2=9\)
=>19x+50=126
=>19x=76
hay x=4
e: \(\Leftrightarrow2\cdot3^x=10\cdot3^{12}+8\cdot3^{12}=18\cdot3^{12}\)
\(\Leftrightarrow3^x=3^2\cdot3^{12}=3^{14}\)
hay x=14
f: \(\Leftrightarrow3\left(x+2\right):7=30\)
=>3(x+2)=210
=>x+2=70
hay x=68
g: \(2480-1570+200-x+5=1010\)
=>1115-x=1010
hay x=105
a) Ta có: \(x^2\ge0\forall x\in Q\)
\(y^2\ge0\forall x\in Q\)
\(\Rightarrow x^2+y^2+2014\ge2014\forall x\in Q\)
Dấu giá trị nhỏ nhất của biểu thức là 2014, xảy ra khi \(\left\{{}\begin{matrix}x^2=0\\y^2=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0\\y=0\end{matrix}\right.\)
b, Ta có: \(\left(x+30\right)^2\ge0\forall x\in Q\)
\(\left(y-4\right)^2\ge0\forall x\in Q\)
\(\Rightarrow\left(x+30\right)^2+\left(y-4\right)^2+17\ge17\forall x\in Q\)
Dấu giá trị nhỏ nhất của biểu thức là 17, xảy ra khi \(\left\{{}\begin{matrix}\left(x+30\right)^2=0\\\left(y-4\right)^2=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-30\\y=4\end{matrix}\right.\)
c, Ta có: \(\left(y-9\right)^2\ge0\forall x\in Q\)
\(\left|x-3\right|\ge0\forall x\in Q\)
\(\Rightarrow\left(y-9\right)^2+\left|x-3\right|^2-1\ge-1\forall x\in Q\)
Dấu giá trị nhỏ nhất của biểu thức là -1 xảy ra khi \(\left\{{}\begin{matrix}\left(y-9\right)^2=0\\\left|x-3\right|=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=9\\x=3\end{matrix}\right.\)
a; -2\(x\) - 3.(\(x-17\)) = 34 - 2.( - \(x\) + 25)
- 2\(x\) - 3\(x\) + 51 = 34 + 2\(x\) - 50
2\(x\) + 2\(x\) + 3\(x\) = - 34 + 50 + 51
7\(x\) = 67
\(x\) = 67 : 7
\(x\) = \(\dfrac{67}{7}\)
Vậy \(x\) = \(\dfrac{67}{7}\)
b; 17\(x\) + 3.(- 16\(x\) - 37) = 2\(x\) + 43 - 4\(x\)
17\(x\) - 48\(x\) - 111 = 2\(x\) - 4\(x\) + 43
- 31\(x\) - 2\(x\) + 4\(x\) = 111 + 43
- \(x\) x (31 + 2 - 4) = 154
- \(x\) x (33 - 4) = 154
- \(x\) x 29 = 154
- \(x\) = 154 : (-29)
\(x\) = - \(\dfrac{154}{29}\)
Vậy \(x=-\dfrac{154}{29}\)
a) x=0
b) x=46
c) hình như sai đề
d)x=4
e)x=6
f)x=8
h) hình như sai đề
i) x=5
j)x=2
l) x= 15 hoặc x = -15
m) x=5
n) x=18,5
o)x=2
u)x thuộc N
p)x =2
s)x=3
k)x=2
z)x=2
a)2^x+1.2^2014=2^2015
2^x+1=2^2015:2^2014
2^x+1=2^1
=>x+1=1
x=2
b)2x-49=5.3^2
2x-49=45
2x=45+49
2x=94
x=47
c)3^2.(x+14)-5^2=5.2^2
9.(x+14)-25=20
9.(x+14)=45
x+14=5
x=11
d)6x+x=5^11:5^9+3^1
x.(6+1)=28
x.7=28
x=4
e)7x-x=5^21:5^19+3.2^2-7^0
x.(7-1)=36
x.6=36
x=6
f)7x-2x=6^17:6^15+44:11
x.(7-2)=40
x.5=40
x=8
g)4^x=6
=>ko tìm dc x
h)9^x-1=9
=>x-1=1
x=2
i)2^x:2^5=1
2^x-5=2^0
=>x-5=0
x=5
j)/x-2/=0
=>x-2=0
x=2
l)/x-5/=7--3
/x-5/=10
TH1:x-5=10
x=15
th2:x-5=-10
x=-5
m)5x+x=39-3^11:3^9
x.(5+1)=30
x.6=30
x=5
u)0:x=0
=>x thuộc Q
p)3^x=9
3^x=3^2
=>x=2
s)4^x=64
4^x=4^3
=>x=3
k)9^x-1=9
=>x-1=1
x=2
z)x^4=16
x^4=2^4
=>x=2
có mấy câu bị trùng đề bài ấy , bạn ạ
a) pt <=> \(\frac{x\left(x+1\right)}{2}=500500\)
<=> \(x^2+x=1001000\)
<=> \(x^2-1000x+1001x-1001000=0\)
<=> \(\left(x-1000\right)\left(x+1001\right)=0\)
<=> \(\orbr{\begin{cases}x=1000\\x=-1001\end{cases}}\)
Do \(x>0\)=> \(x=1000\)
b)
<=> \(2x=210\)
<=> \(x=105\)
c)
<=> \(6x-81=3.7\)
<=> \(x=17\)
d)
<=> \(125-5\left(3x-1\right)=5^2\)
<=> \(5\left(3x-1\right)=100\)
<=> \(3x-1=20\)
<=> \(x=7\)
e)
<=> \(4^{x+1}+1=65\)
<=> \(4^{x+1}=64\)
<=> \(x+1=3\)
<=> \(x=2\)
j)
<=> \(2\left(2x-3\right)=14\)
<=> \(2x-3=7\)
<=> \(x=5\)
a) \(8x+56:14=60\)
\(\Rightarrow8x+4=60\)
\(\Rightarrow8x=56\)
\(\Rightarrow x=\dfrac{56}{8}\)
\(\Rightarrow x=7\)
b) Mình làm rồi nhé !
c) \(41-2^{x+1}=9\)
\(\Rightarrow2^{x+1}=41-9\)
\(\Rightarrow2^{x+1}=32\)
\(\Rightarrow2^{x+1}=2^5\)
\(\Rightarrow x+1=5\)
\(\Rightarrow x=4\)
d) \(3^{2x-4}-x^0=8\)
\(\Rightarrow3^{2x-4}-1=8\)
\(\Rightarrow3^{2x-4}=9\)
\(\Rightarrow3^{2x-4}=3^2\)
\(\Rightarrow2x-4=2\)
\(\Rightarrow2x=6\)
\(\Rightarrow x=3\)
g) \(65-4^{x+2}=2014^0\)
\(\Rightarrow65-4^{x+2}=1\)
\(\Rightarrow4^{x+2}=64\)
\(\Rightarrow4^{x+2}=4^3\)
\(\Rightarrow x+2=3\)
\(\Rightarrow x=1\)
i) \(120+2\left(4x-17\right)=214\)
\(\Rightarrow2\left(4x-17\right)=214-120\)
\(\Rightarrow2\left(4x-17\right)=94\)
\(\Rightarrow4x-17=47\)
\(\Rightarrow4x=47+17\)
\(\Rightarrow4x=64\)
\(\Rightarrow x=16\)
a: \(8x+56:14=60\)
=>8x+4=60
=>8x=60-4=56
=>x=56/8=7
b: \(5^{2x-3}-2\cdot5^2=5^2\cdot3\)
=>\(5^{2x-3}=5^2\cdot3+2\cdot5^2=5^3\)
=>2x-3=3
=>2x=6
=>x=3
c: \(41-2^{x+1}=9\)
=>\(2^{x+1}=41-9=32\)
=>x+1=5
=>x=4
d: \(3^{2x-4}-x^0=8\)
=>\(3^{2x-4}-1=8\)
=>\(3^{2x-4}=8+1=9\)
=>2x-4=2
=>2x=6
=>x=3
g: \(65-4^{x+2}=2014^0\)
=>\(65-4^{x+2}=1\)
=>\(4^{x+2}=65-1=64\)
=>x+2=3
=>x=1
i: 120+2(4x-17)=214
=>2(4x-17)=214-120=94
=>4x-17=94/2=47
=>4x=64
=>\(x=\dfrac{64}{4}=16\)