\(\left(2-\frac{x}{13}\right)^3=\frac{1331}{2197}\)
=> \(\left(2-\frac{x}{13}\right)^3=\left(\frac{11}{13}\right)^3\)
=> \(2-\frac{x}{13}=\frac{11}{13}\)
=> \(\frac{x}{13}=2-\frac{11}{13}=\frac{2\cdot13-11}{13}=\frac{15}{13}\)
=> x = 15
\(\left(2-\frac{x}{13}\right)^3=\frac{1331}{2197}\)
=> \(\left(2-\frac{x}{13}\right)^3=\left(\frac{11}{13}\right)^3\)
=> \(2-\frac{x}{13}=\frac{11}{13}\)
=> \(\frac{x}{13}=2-\frac{11}{13}=\frac{2\cdot13-11}{13}=\frac{15}{13}\)
=> x = 15
Bài 1: Tìm x
a) \(\left(x-2\right)^4=256\)
b) \(\frac{x^4}{256}=81\)
c) \(125\left(x+\frac{4}{5}\right)^3=729\)
e) \(7^x+2+7x=50\)
f) \(9.13^{x-1}+\frac{4}{169}.13^{x+1}=2197\)
Viết số dưới dạng luỹ thừa cơ số .
CMR:\(\frac{m}{n}=1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{1331}\)chia hết cho 1997 biết (m,n)=1 (m,n nguyên tố cùng nhau)
\(\frac{1330}{1331}-\frac{7}{1.8}-\frac{19}{8.27}-\frac{37}{27.64}-...-\frac{331}{1000.1331}\)
Bài 1 Tính
a, 12/21-3/7+-2/3
b,(-25/13)+(-9/17)+12/13+(-25/17)
c,5/9.7/13+5/9.9/13-5/9.3/13
Bài 2 tìm x
a,2/3x+5/7=3/10
b,x:5/2-1/2=-2/3
c,|x-3/4|-1/2=0
tìm x
a, 11/13 -( 5/42 - x) = - (15/28 - 11/13)
b, x +1/3 = 2/5-(-1/3)
c, 2/3 x +5/7 =3/10
d, 3/7-x = 1/4 - (-3/5)
e, -21/13 x + 1/3 = -2/3
tìm số hữu tỉ x , biết ; x+2/11+x+2/13+x+3/13=x+2/14+x+2/15
1,Thực hiện phép tính
a)- 4/13 . 5/17 + - 12/13 * 4/17 + 8/13
b)v0,36 * v25/36 + 1/4
2,Tìm x biết :
a) | x - 3/2 | = 2
b) ( 1/2 ) ^ x +1 - 1/2 = - 3/8
Bài 1:
a,11/125-17/18-5/7+4/9+17/14
b,(7+7/5-2/3)-(4+4/5+3/8)+(3-3/5+2/3+3/8)
c,-13/25.5/32.23/-13.(-64)
Bài 2:
a,11/13-(3/42-x)=-(13/28-11/13)
b,x2/3x+5/7=3/10
c,x-21/13x+1/3=-2/3