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a. \(3^2.x+2^2.x=26.2^2-13\)
\(=x.\left(3^2+2^2\right)=26.4-13\)
\(\Rightarrow x.\left(9+4\right)=104-13\)
\(\Rightarrow x.13=91\)
\(\Rightarrow x=91:13=7\)
Vậy.......
b. \(\left(2x-1\right)^2=49\)
\(\Rightarrow\left(2x-1\right)^2=\left(\pm7\right)^2\)
\(\Rightarrow\left[{}\begin{matrix}2x-1=7\\2x-1=-7\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}2x=8\\2x=-6\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=4\\x=-3\end{matrix}\right.\)
Vậy........
c. \(50-5\left(x+4\right)=15\)
\(\Rightarrow5\left(x+4\right)=50-15=35\)
\(\Rightarrow\left(x+4\right)=35:5=7\)
\(\Rightarrow x=7-4=3\)
Vậy......
d. \(4.\left[\left(30+3^3\right):10+97\right]-300\)
\(=4.\left[\left(30+9\right):10+97\right]-300\)
\(=4.\left[39:10+97\right]-300\)
\(=4.\left[\dfrac{39}{10}+97\right]-300\)
\(=4.\left[\dfrac{1009}{10}\right]-300\)
\(=\dfrac{2018}{5}-300\)
\(=\dfrac{518}{5}\)
e.\(2^3-5^3:5^2:5^2.2^2\)
\(=2^3-5^{-1}.2^2\)
\(=8-\dfrac{1}{5}.4\)
\(=8-\dfrac{4}{5}\)
\(=\dfrac{36}{5}\)
a) 32 . x + 22. x = 26 . 22 _ 13
\(\Rightarrow\) (32 + 22) . x = 26 . 4 - 13
(9 + 4) . x = 104 - 13
13x = 91
x = 91 : 13
x = 7.
b) (2x - 1)2 = 49
\(\Rightarrow\) (2x - 1)2 = 72
\(\Rightarrow\) 2x - 1 = 7
2x = 7 + 1
2x = 8
x = 8 : 2
x = 4.
c) 50 - 5(x + 4) = 15
5(x + 4) = 50 - 15
5(x + 4) = 35
x + 4 = 35 : 5
x + 4 = 7
x = 7 - 4
x = 3.
d) 4 . [(30 + 33) : 10 + 97] - 300
= 4 . [(30 + 27) : 10 + 97] - 300
= 4 . [57 : 10 + 97] - 300
= 4 . [5,7 + 97] - 300
= 4 . 102,7 - 300
= 410,8 - 300
= 110,8.
e) 23 - 53 : 52 : 52 . 22
= 23 - 5 : 25 . 4
= 8 - 0,2 . 4
= 7,8 . 4
= 31,2.
chi con 10 ngay nua thoi la ki kiem tra nay se ket thuc
a . 32 . X + 22.X=26.22_13
=> 9 . x + 4 . x = 26 . 4 - 13
=> x . ( 9 + 4 ) = 26 . 4 - 13
=> x . 13 = 26 . 4 - 13
=> x . 13 = 104 - 13
=> x . 13 = 91
=> x = 91 : 13
=> x = 7
Vậy : x = 7
b.(2x-1)2=49
=> ( 2x - 1 )2 = 72
=> 2x - 1 = 7
=> 2x = 7 + 1
=> 2x = 8
=> x = 8 : 2
=> 4
Vậy x = 4
c.50-5(x+4 )=15
=> 5( x + 4 ) = 50 - 15
=> 5( x + 4 ) = 35
=> x + 4 = 35 : 5
=> x + 4 = 7
=> x = 7 - 4
=> x = 3
Vậy x = 3
d. 4.[(30+33):10+97]-300
=> 4 . [( 30 + 27 ) : 10 + 97 ] - 300
=> 4 . [ 57 : 10 + 97 ] - 300
=> 4 . [ 5,7 + 97 ] - 300
=> 4 . 102,7 - 300
=> 410,8 - 300
=> 110,8
Vậy đáp số bằng 110,8
e.23-53:52:52.22
=> 8 - 125 : 25 : 25 . 4
=> 8 - 5 : 25 .4
=> 8 - 5 : 100
=> 8 - 0,05
=> 7,95
Vậy đáp số bằng 7,95
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