( 2x -4)38= ( 2x-4)48
a) 5 . x - 38 : 19 = 13
b) 84 - 4 . ( 2x + 1) = 48
5.x - 38:19 = 13
=> 5x - 2 = 13
=> 5x = 15
=> x = 3
84-4(2x+1) = 48
=> 4(2x+1) = 36
=> 2x + 1 = 9
=> 2x = 10
x = 5
A)4+96:[(2⁴x2+4):3²
B)15²-2x[81-(3+4)²]
C)50+[30-2x(14-48:4²)]
Giúp e với ạ
Tìm x:
a) x(2-x)+(x2+x)=7
b) (2x+1)2-x(4-5x)=17
c) (4-x)2-(2x+1)2=0
d) (2x3-8x2+10x) : (2x)=0
e) (4x4-16x-48) : (-2x)2=0
a: Ta có: \(x\left(2-x\right)+\left(x^2+x\right)=7\)
\(\Leftrightarrow2x-x^2+x^2+x=7\)
\(\Leftrightarrow3x=7\)
hay \(x=\dfrac{7}{3}\)
b: Ta có: \(\left(2x+1\right)^2-x\left(4-5x\right)=17\)
\(\Leftrightarrow4x^2+4x+1-4x+5x^2=17\)
\(\Leftrightarrow9x^2=16\)
\(\Leftrightarrow x^2=\dfrac{16}{9}\)
hay \(x\in\left\{\dfrac{4}{3};-\dfrac{4}{3}\right\}\)
c: Ta có: \(\left(x-4\right)^2-\left(2x+1\right)^2=0\)
\(\Leftrightarrow\left(x-4-2x-1\right)\left(x-4+2x+1\right)=0\)
\(\Leftrightarrow\left(x+5\right)\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-5\\x=1\end{matrix}\right.\)
d: ta có: \(\dfrac{2x^3-8x^2+10x}{2x}=0\)
\(\Leftrightarrow x^2-4x+5=0\)
\(\Leftrightarrow\left(x-2\right)^2+1=0\)(vô lý)
Tìm x, biết:
4 * 2^x42 - 2x = 480
(2x^2 + 1)*(x-3)=0
48-(15-x)^5=48
(2x2 + 1)(x-3)=0
\(\Rightarrow\orbr{\begin{cases}2x^2+1=0\\x-3=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}2x^2=-1\Rightarrow x^2=-\frac{1}{2}\left(vl\right)\\x=3\end{cases}}\)
Vậy x=3
48-(15-x)5=48
(15-x)5=48-48
(15-x)5=0
=> 15-x =0
x =15-0
x =15
Vậy x=15
Tìm x
2x - 3 =17
4² - 3x =27.3 -77
48 + 2x = 3.2³
( 13x -12² ) : 5 =5
2x - 3 = 17
2x = 17 + 3
2x = 20
x = 20 : 2
x = 10
---------------
4² - 3x = 27.3 - 77
16 - 3x = 81 - 77
16 - 3x = 4
3x = 16 - 4
3x = 12
x = 12 : 3
x = 4
----------------
48 + 2x = 3.2³
48 + 2x = 3.8
48 + 2x = 24
2x = 24 - 48
2x = -24
x = -24 : 2
x = -12
----------------
(13x - 12²) : 5 = 5
13x - 144 = 5.5
13x - 144 = 25
13x = 25 + 144
13x = 169
x = 169 : 13
x = 13
\(2x-3=17\)
\(2x=17+3\)
\(2x=20\)
\(x=20:2\)
\(x=10\)
____
\(4^2-3x=27.3-77\)
\(16-3x=81-77\)
\(16-3x=4\)
\(3x=16-4\)
\(3x=12\)
\(x=12:3\)
\(x=4\)
_____
\(48+2x=3.2^3\)
\(48+2x=3.8=24\)
\(2x=24-48\)
\(2x=\left(-24\right)\)
\(x=\left(-24\right):2\)
\(x=\left(-12\right)\)
____
\(\left(13x-12^2\right):5=5\)
\(\left(13x-144\right):5=5\)
\(13x-144=5.5\)
\(13x-144=25\)
\(13x=25+144\)
\(13x=169\)
\(x=169:13\)
\(x=13\)
Bài 1
a. -25 . 21.(-2)2.(-|-3|) .(-1)2n ( n ∈ N sao)
b. 35.18-5.7.18
c. 24 . (16-5) -16.(24-5)
d.29 . (19-13) - 19 . (29-13)
e. -48 .(-78) +48 . (-21)
f. 31.(-18)+31.(-18) -31
Bài 2 : Tính tổng:
a. 1+(-2)+3+(-4)+........+19+(-20)
b. 2-4+6-8+...+48-50
c. 1+2-3-4+.....+97+98-99-100
Bài 3: Tìm x
a. -2x - (x -17) = 34 - (-x +25)
b. 17.x+(16.x-37) = 2x +43
c. |2.x+1| -19 = -7
d. 12-2.(-x+3)2= -38
e. -20+3.(2x+1)3= -101
tím x
a) 12 . ( x - 4 ) + 3 . ( 2x + 5 ) = 16
b) -10 . ( 2x + 4 ) - 2 . ( 6 - 15x ) = 48
a) 2x+3 chia het 2x-1
b)3x+1 chia het 11-2x
c)(x+5)(y-3)=15
d)(2x-1)(y+2) =24 e)1+3+5+7+......+(2x+1) g)2+4+6+...+2x =756
a, \(2x+3⋮2x-1\)
\(2x-1+4⋮2x-1\)
\(4⋮2x+1\)hay \(2x+1\inƯ\left(4\right)=\left\{1;2;4\right\}\)
2x + 1 | 1 | 2 | 4 |
2x | 0 | 1 | 3 |
x | 0 | 1/2 | 3/2 |
c, \(\left(x+5\right)\left(y-3\right)=15\Leftrightarrow x+5;y-3\inƯ\left(15\right)=\left\{1;3;5;15\right\}\)
x + 5 | 1 | 3 | 5 | 15 |
y - 3 | 15 | 5 | 3 | 1 |
x | -4 | -2 | 0 | 10 |
y | 18 | 8 | 6 | 4 |
38-2/3*(3x-4)=-5 1/2x-16