Tìm x : 973-x:34+12=729
Tìm x ∈ N , biết.
a) 3 x + 1 : 3 4 = 81
b) 3 x + 3 . 3 x + 1 = 729
c) 2 x + 3 . 2 x = 128
d) 23 + 3 x = 5 6 : 5 3
e) 2 x + 2 x + 4 = 272
Tìm x ∈ N, biết.
a, 3 x + 1 : 3 4 = 81
b, 3 x + 3 . 3 x + 1 = 729
c, 2 x + 3 . 2 x = 128
d, 23 + 3 x = 5 6 : 5 3
e, 2 x + 2 x + 4 = 272
a, 3 x + 1 : 3 4 = 81
3 x - 3 = 3 4
x – 3 = 4
x = 7
Vậy x = 7
b, 3 x + 3 . 3 x + 1 = 729
3 2 x + 4 = 3 6
2x + 4 = 6
x = 1
Vậy x = 1
c, 2 x + 3 . 2 x = 128
2 2 x + 3 = 2 7
2x + 3 = 7
x = 2
Vậy x = 2
d, 23 + 3 x = 5 6 : 5 3
23 + 3 x = 5 3
23 + 3x = 125
3x = 102
x = 34
Vậy x = 34
e, 2 x + 2 x + 4 = 272
2 x + 2 x . 2 4 = 272
2 x ( 1 + 2 4 ) = 272
2 x . 17 = 272
2 x = 16
2 x = 2 4
x = 4
Vậy x = 4
Tìm x biết :
(x^4)^2=x^12 : x^5 (x khác 0)x^8 =729x x 8+29=973
tìm x
X x 8 + 29 = 973
X x 8 = 973 - 29
X x 8 = 944
X = 944 : 8
X = 118
Tìm x, biết:
a ) | x | − 1 2 = 3 4 ; b ) x − 1 2 = 1 c ) x − 1 2 − 3 4 = 1 4 ; d ) 1 20 − 3 2 − x = 1 40 e ) x + 1 3 2 − 4 9 = 0 f ) x + 1 3 2 + 4 9 = 8 9
a ) x = 5 4 x = − 5 4 b ) x = 3 2 x = − 1 2 c ) x = 3 2 x = − 1 2
d ) x = 59 40 x = 61 40 e ) x = 1 3 x = − 1 f ) x = 1 3 x = − 1
tìm x biết/1/729 =(1+1/3+19+...+1/729)x
Tìm X:(X+1/3)+(X+1/9)+(X+1/27)+...+(X+1/729)=4209/729
Giups mình với các bạn.
`Answer:`
\(\left(x+\frac{1}{3}\right)+\left(x+\frac{1}{9}\right)+\left(x+\frac{1}{27}\right)+...+\left(x+\frac{1}{729}\right)=\frac{4209}{729}\)
\(\Leftrightarrow\left(x+\frac{1}{3}\right)+\left(x+\frac{1}{3^2}\right)+\left(x+\frac{1}{3^3}\right)+...+\left(x+\frac{1}{3^6}\right)=\frac{4209}{729}\)
\(\Leftrightarrow6x+\left(\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+...+\frac{1}{3^6}\right)=\frac{4209}{729}\text{(*)}\)
Đặt \(N=\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+...+\frac{1}{3^6}\)
\(\Leftrightarrow3N=1+\frac{1}{3}+\frac{1}{3^2}+...+\frac{1}{3^5}\)
\(\Leftrightarrow3N-N=\left(1+\frac{1}{3}+\frac{1}{3^2}+..+\frac{1}{3^5}\right)-\left(\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+...+\frac{1}{3^6}\right)\)
\(\Leftrightarrow2N=1-\frac{1}{3^6}\)
\(\Leftrightarrow2N=\frac{728}{729}\)
\(\Leftrightarrow N=\frac{364}{729}\)
\(\text{(*)}\Leftrightarrow6x+\frac{364}{729}=\frac{4209}{729}\)
\(\Leftrightarrow6x=\frac{3845}{729}\)
\(\Leftrightarrow x=\frac{3845}{4374}\)
Tìm x
X × 12 = 150 × 2 3 4 ÷ x = 1 2
Tìm x, biết
a) x − 2 5 : 2 3 = 3 4
b) x + − 3 4 − 1 2 = 2 3 . 3 5
c) x − 2 7 = − 9 14 . − 4 3
a ) x − 2 5 : 2 3 = 3 4 x − 2 5 = 3 4 . 2 3 x − 2 5 = 1 2 x = 9 10
b ) x + − 3 4 − 1 2 = 2 3 . 3 5 x + − 3 4 − 1 2 = 2 5 x + − 3 4 = 9 10 x = 33 20
c ) x − 2 7 = − 9 14 . − 4 3 x − 2 7 = 6 7 +) x − 2 7 = 6 7 x = 8 7 +) x − 2 7 = − 6 7 x = − 4 7