7 x - x = 521 : 519 + 3.22 - 70
2x : 23 = 16
32.x + 3 - 9x+1 = 2.310
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\(7x-x=5^{21}:5^{19}+3.2^2-7^0\)
\(6x=5^2+3.2-1\)
\(6x=25+12-1\)
\(6x=36\)
\(x=6\)
a) \(5x+x=39-3^{11}:3^9\)
\(\Leftrightarrow6x=39-3^2\)
\(\Leftrightarrow6x=30\)
\(\Leftrightarrow x=5\)
b) \(2^x:2^5=16\)
\(\Leftrightarrow2^x:2^5=2^4\)
\(\Leftrightarrow2^x=2^4.2^5\)
\(\Leftrightarrow2^x=2^9\)
\(\Leftrightarrow x=9\)
c) \(7x-x=5^{21}:5^{19}+3.2^2-7^0\)
\(\Leftrightarrow6x=5^2+3.4-1\)
\(\Leftrightarrow6x=36\)
\(\Leftrightarrow x=6\)
d) \(7x-2x=6^{17}:6^{15}+44:11\)
\(\Leftrightarrow5x=6^2+4\)
\(\Leftrightarrow5x=40\)
\(\Leftrightarrow x=8\)
a)⇔6x=39-32
⇔6x=30
⇔ x=5
b)2x:25=16
⇔2x=24.25
⇔ 2x=29
⇔ x=9
c)⇔6x=52+3.22-1
⇔ 6x= 36
⇔ x=6
d)⇔5x=62+4
⇔ 5x=40
⇔ x=8
a: \(\Leftrightarrow6x=30\)
hay x=5
b: \(\Leftrightarrow6x=25+12-1=36\)
hay x=6
a: \(\Leftrightarrow8x=108+12=120\)
hay x=15
b: \(\Leftrightarrow6x=60\)
hay x=10
Bai 2 :
\(\hept{\begin{cases}x+y=7\\x-7=13\end{cases}\Leftrightarrow\hept{\begin{cases}x+y=7\\x=20\end{cases}}}\)
Thay x vào phương trình đầu ta có :
\(20+y=7\Leftrightarrow y=-13\)
Vậy \(\left\{x;y\right\}=\left\{20;-13\right\}\)
Thử \(20-13=7\); \(20-7=13\)( thỏa mãn )
`#3107.101107`
a)
\(5\left(x-1\right)^3=40\\\Rightarrow\left(x-1\right)^3=40\div5\\ \Rightarrow\left(x-1\right)^3=8\\ \Rightarrow\left(x-1\right)^3=2^3\\ \Rightarrow x-1=2\\ \Rightarrow x=2+1\\ \Rightarrow x=3\)
Vậy, `x = 3`
b)
\(3^{2x+1}+9^x=324?\\ \Rightarrow3^{2x}\cdot3+3^{2x}=324\\ \Rightarrow3^{2x}\cdot\left(3+1\right)=324\\ \Rightarrow3^{2x}\cdot4=324\\ \Rightarrow3^{2x}=81\\ \Rightarrow3^{2x}=3^4\\ \Rightarrow2x=4\\ \Rightarrow x=2\)
Vậy, `x = 2`
c)
\(5^x-13=3\cdot2^2\\ \Rightarrow5^x-13=12\\ \Rightarrow5^x=12+13\\ \Rightarrow5^x=25\\ \Rightarrow5^x=5^2\\ \Rightarrow x=2\)
Vậy, `x = 2`
d)
\(8^x+2^{3x+1}=192\\ \Rightarrow2^{3x}+2^{3x}\cdot2=192\\ \Rightarrow2^{3x}\left(1+2\right)=192\\ \Rightarrow2^{3x}\cdot3=192\\ \Rightarrow2^{3x}=64\\ \Rightarrow2^{3x}=2^6\\ \Rightarrow3x=6\\ \Rightarrow x=2\)
Vậy, `x = 2.`
a) 89-(73-x) = 20
=> 73+x =89-20
=> 73+x=69
=> x=69-73
=> x=-4
b) (x+7)-25=13
=> x+7=13+25
=> x+7=38
=> x=38-7
=> x=31
c) 98-(x+4)=20
=> x+4=98-20
=> x+4=78
=> x=78-4
=> x=73
d) 140:(x-8)=7
=> x-8=140:7
=> x-8=20
=> x=20+8
=> x=28
e) 4(x+41)=400
=> x+41=400:4
=> x+41=100
=> x=100-41
=> x=59
f) x-[42+(-28)]=-8
=> x-14=-8
=> x=-8+14
=> x=6
\(bn\)\(xem\)\(lai\)\(giup\)\(mk\)\(cho\)\(\frac{x+522}{7}\)\(neu\)\(thay\)\(bang\)\(\frac{x+552}{7}\)\(thi\)\(dug\)\(hon\)
thế thì bạn giải thử xem cô t ra đề thế mà ừ thì cứ cho là x + 552 cx đc
7x - x = 521: 519 + 3.22 - 70
=> 6x = 52 + 3.4 - 1
=> 6x = 25 + 12 - 1
=> 6x = 36
=> x = 36 : 6
=> x = 6
2x : 23 = 16
=> 2x = 16.23
=> 2x = 128
=> 2x = 27
=> x = 7
32x + 3 - 9x + 1 = 2.310
=> 32x + 3 - 32x + 2 = 2.310
=> 32x + 2. 3 - 32x + 2 = 2.310
=> 32x + 2. (3 - 1) = 2.310
=> 32x + 2.2 = 2.310
=> 32x + 2 = 310
=> 2x + 3 = 10
=> 2x = 10 - 3
=> 2x = 7
=> x = 7/2
a) \(7x-x=5^{21}:5^{19}+3.2^2-7^0\)
\(\Rightarrow6x=25+12-1\)
\(\Rightarrow x=6\)
b) \(2^x:2^3=16\)
\(\Rightarrow2^x=2^4.2^3=2^7\)
\(\Rightarrow x=7\)
c) \(3^{2x+3}-9^{x+1}=2.3^{10}\)
\(\Rightarrow9^x.27-9^x.9=2.3^{10}\)
\(\Rightarrow9^x.18=2.3^{10}\)
\(\Rightarrow9^x=3^8=9^4\)
\(\Rightarrow x=4\)