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a, 89 - (73 - \(x\)) = 20
73 - \(x\) = 89 - 20
73 - \(x\) = 69
\(x\) = 73 - 69
\(x\) = 4
b, 7\(x\) - 2\(x\) = 617:615 + 44:11
5\(x\) = 62 + 4
5\(x\) = 36 + 4
5\(x\) = 40
\(x\) = 40: 5
\(x\) = 8
A, 89-(73-x)=20
73-x =89-20
73-x =69
x = 73-69
x = 4
B, 62-(2x-3):3 = 23
(2x-3):3 = 62-23
(2x-3):3 = 39
2x-3 = 39.3
2x-3 = 117
2x = 117+3
2x = 120
x = 120:2
x = 60
C, 4(x-3) = 72 - 110
4(x-3) = 49 - 1
4(x-3) = 48
x-3 = 48:4
x-3 = 12
x = 12+3
x = 15
D, 32 (x+4)-52= 5.22
9(x+4)-25 = 5.4
9(x+4)-25 = 20
9(x+4) = 20+25
9(x+4) = 45
x+4 = 45:9
x+4 = 5
x = 5-4
x = 1
(Làm có hơi dài dòng nhưng đầy đủ lắm)
a, 89-(73-x)=20 b. 62-( 2x -3): 3=23 c, 4(x-3) = 72-11o d, 32 (x+4)-52 = 5.22
(73-x)=89-20 (2x - 3 ):3 = 62-23 4(x-3)=49-1 32(x+4) - 52= 5.4=20
73-x = 69 (2x - 3): 3= 39 4(x-3) =48 32(x+4)-25 =20
x = 73-69 (2x - 3)= 39: 3 x-3 = 48 :8 32(x+4)=20+25=45
x = 4 2x -3 =13 x-3 = 6 9(x+4)=45
2x= 13 + 3 x=6+3 x+4=45:9
2x= 16 x= 9 x+4=5
x=16:2 x=5-4
x= 8 x=1
chỗ nào ko hiểu cứ hỏi mik nhé
a) \(5x+x=39-3^{11}:3^9\)
\(6x=39-3^2\)
\(x=30:6\)
\(x=5\)
vậy \(x=5\)
b) \(7x-x=5^{21}:5^{19}+3.2^2-7^0\)
\(6x=5^2+12-1\)
\(6x=36\)
\(x=6\)
vậy \(x=6\)
câu c tương tự nha
a. 7x-2x=617:615 + 44:11
=> 5x=62 + 4
=> 5x=36 + 4
=> 5x=40
=> x=40:5
=> x=8
b. 2x.(22)2=(23)2
=> 2x.24=26
=> 2x=26:24
=> 2x=22
=> x=2.
c. Theo đề => \(x\in BC\left(5,7\right)\)
Ta có: 5=5; 7=7
=> BCNN(5, 7)=5.7=35
=> \(x\in BC\left(5,7\right)=B\left(35\right)=\left\{0;35;70;105;140;175;210;245;280;315;...\right\}\)
Mà x < 300
Vậy x thuộc { 0; 35; 70; ...; 245; 280 }.
\(5x+2x=6^2-5^0\Leftrightarrow5x+2x=6^2-1\)
\(\Leftrightarrow5x-2x=36-1\Leftrightarrow5x-2x=35\Leftrightarrow x\left(5+2\right)=35\)
\(\Leftrightarrow7x=35\Leftrightarrow x=35:7\Leftrightarrow x=5\)
\(5x+x=150:2+3\Leftrightarrow5x+x=75+3\)
\(\Leftrightarrow5x+x=78\Leftrightarrow x\left(5+1\right)=78\Leftrightarrow x6=78\)
\(\Leftrightarrow x=78:6\Leftrightarrow x=13\)
a) 5x + 2x = 62 - 50
7x = 35 => x = 5
b) 5x + x = 150 : 2 + 3
6x = 78 => x = 13
c) 6x + x = 511 : 59 + 31
7x = 28 => x = 4
d) 5x + 3x = 36 : 33 x 4 + 12
8x = 120 => x = 15
e) 4x + 2x = 68 - 219 : 216
6x = 60 => x = 10
f) 5x + x = 39 - 311 : 39
6x = 30 => x = 5
g) 7x - x = 521 : 519 + 3 x 22 - 70
6x = 36 => x = 6
h) 7x - 2x = 617 : 615 + 44 : 11
5x = 40 => x = 8
1) \(2^{x+1}\cdot2^{2014}=2^{2015}\)\(\Leftrightarrow2^{2014x+2014}=2^{2015}\)\(\Leftrightarrow2014x+2014=2015\)\(\Leftrightarrow x=\frac{1}{2014}\)
2) \(7x-2x=\frac{6^{17}}{6^{15}}+\frac{44}{11}\)\(\Leftrightarrow5x=6^2+4=36+4=40\)\(\Leftrightarrow x=\frac{40}{5}=8\)
3) \(3^x=9\)\(\Leftrightarrow3^x=3^2\)\(\Leftrightarrow x=2\)
4) \(7x-x=\frac{5^{21}}{5^{19}}+3\cdot2^2-7^0\)\(\Leftrightarrow6x=5^2+3\cdot4-1=25+12-1=36\)\(\Leftrightarrow x=6\)
5) \(4^x=64\)\(\Leftrightarrow4^x=4^3\)\(\Leftrightarrow x=3\)
6) \(9^{x-1}=9\)\(\Leftrightarrow x-1=1\)\(\Leftrightarrow x=0\)
7) \(\frac{2^x}{2^5}=1\)\(\Leftrightarrow2^{x-5}=2^0\)\(\Leftrightarrow x-5=0\)\(\Leftrightarrow x=5\)
8) \(\left(5x-9\right)^3=216\)\(\Leftrightarrow\left(5x-9\right)^3=6^3\)\(\Leftrightarrow5x-9=6\)\(\Leftrightarrow5x=15\)\(\Leftrightarrow x=3\)
9) \(5\cdot3^{7x-11}=135\)\(\Leftrightarrow5.3^{7x-11}=5.3^3\)\(\Leftrightarrow3^{7x-11}=3^3\)\(\Leftrightarrow7x-11=3\)\(\Leftrightarrow7x=14\Leftrightarrow x=2\)
10) \(2.3^x=19\cdot3^8-81^2\)\(\Leftrightarrow2.3^x=19\cdot3^8-3^8=18.3^8=2.3^{11}\)\(\Leftrightarrow3^x=3^{11}\Leftrightarrow x=11\)
Đây là cách làm của mình. Bạn có thể chỉnh sửa tuỳ ý theo cách làm của bạn nhé ^^
Học tốt ^3^
A, 89 -(73-x)=20
=> 73 - x = 89 - 20
=> 73 - x = 69
=> x = 73 - 69
=> x = 4
B, 7x - 2x = 617:615 + 44:11
=> ( 7 - 2 ) x = 36 + 4
=> 5x = 40
=> x = 8
C, x - [ 42+(-28)]=-8
=> x - 14 = - 8
=> x = - 8 + 14
=> x = 6
D, 62 - (2x-3):3=23
=> ( 2x - 3 ) : 3 = 62 - 23
=> ( 2x - 3 ) : 3 = 39
=> 2x - 3 = 117
=> 2x = 120
=> x = 60
E, 4(x-3)=72 - 110
=> 4 ( x - 3 ) = 49 - 1
=> 4 ( x - 3 ) = 48
=> x - 3 = 12
=> x = 15