biet 210.(2^2)^10....(2^10)^10=2n.vậy n=?
biet 210 x (22)10x...x(210)10 = 2n. tìm b
Tìm n,biết:2+4+6+8+10+....+2n=210
Vế trái có (2n-2):2+1=n-1+1=n số hạng
=> Vế trái = (2+2n).n:2=n(n+1)
=> n(n+1)=210=14.15
vì n va n+1 la 2 số tự nhiên liên tiếp nên suy ra n=14
Tính:
D= 10/100 + 10/150 + 10/210 +...+ 10/1200
E= 1.2 + 2.3 + 3.4 +...+ 99.100
F= 1² + 2² + 3² +...+ 97² + 98²
tìm x c N, biet :
7x + x = 32 . 10 + 6
120 - 2 . ( x - 1 ) = 1010 : 108
a) \(7x+x=3^2.10+6\) \(\Rightarrow8x=96\) \(\Rightarrow x=\frac{96}{8}=12\)
b) \(120-2\left(x-1\right)=10^{10}:10^8\) \(\Rightarrow120-2\left(x-1\right)=10^{10-8}\)
\(120-2\left(x-1\right)=100\)
\(2\left(x-1\right)=120-100=20\)
\(x-1=\frac{20}{2}=10\)
\(\Rightarrow x=10+1=11\)
a) <=> 8x= 96 => x=12
b) 120- 2(x-1) = 102
<=> 2(x-1)=120 - 102= 20
<=>x-1= 10 Suy ra: x=10+1=11
a, 7x + x = 32 . 10 + 6
8x = 96
x = 96 : 8
x = 12
b. 120 - 2 . ( x - 1 ) = 1010 : 108
120 - 2 . ( x - 1 ) = 100
2. ( x- 1 ) = 120 - 100
2 . ( x - 1 ) = 20
x - 1 = 20 : 2
x - 1 = 10
x = 10 + 1
x = 11
a) Tính 12 - 4.
Tách: 12 = 10 + 2
10 - 4 = ?
? + 2 = ?
12 - 4 = ?
b) Tính 13 - 6.
Tách 13 = 10 + ?
10 - ? = ?
? + ? = ?
13 - 6 = ?
biet rang 1^2+2^2+3^2+....+10^2=385.Tim x biet x+10^2+12^2+14^2+...+20^2=2011+1^2+3^2+...+9^2
biet x^2 + 6x + 4^n - 2^n+1 + 10 = 0
tinh x + n = ?
210-5x=200
210-5(x-10)=200
450:[41-(2x-5)]= 3^2.5
210:x-10=20
(5x-39).7+3=80
(2x+1):7=2^2.3^2
lưu ý:^ là mũ
VD3^2=ba mũ hai
làm đầy đủ hộ mình nha
a)210-5x=200
5x=210-200
5x=10
x=10:2
x=5
B)210-5(x-10)=200
5(x-10)=210-200
5(x-10)=10
x-10=10:5=2
x=2+10=12
c)450:[41-(2x-5)]=3 mũ 2 .5
450:[41+5-2x]=45
41+5-2x=450:45
41+5-2x=10
2x=36
x=18
D)210:x-10=20
210:x=20+10
210:x=30
x=210:30
x=7
E)(5x-39).7+3=80
(5x-39).7=77
5x-39=11
5x=50
x=10
F(2x+1):7=2 mũ 2 nhân 3 mũ 2
(2x+1):7=36
2x+1=252
2x=251
x=251/2
B= ( -2)+(-10)+(-18)+......+(-210)+(-218)
B={-2}+{-218}.{218-2}:2+1
B={-220}.109
B={-23980}