2181x729+243x81x27/3^2x9^2+18x54x162x9+723x729
a, Thực hiện phép tính:
2181x729+243x81x27/32x92x234+18x54x162x9+723x729
b, So sánh:
A= 20122012+1/20122013+1 và B= 20122011+1/20122012+1
C= 2181x 729 + 243x 81x 27
D= 32 x 92 x 243 + 18x 243x 324+ 723x729
Tính C: D
C=2181x729+243x81x27
C=2181x729+27x9x81x27
C=2181x729+27x27x729
C=2181x729+729x729
C=(2181+729)x729
C=2910x729
(1+2+3+4+5+6+7+8+9)x(2x9-18)
(1+2+3+4+5+6+7+8+9)x(2x9-18)
=(1+2+3+4+5+6+7+8+9)x(18-18)
=(1+2+3+4+5+6+7+8+9)x0
=0
P/s: lần sau đăng đúng môn nha
3+2x9
tim x
a,2/3:2/3xX=1
b, X+X:5x7,5+X:2x9=315
a) \(\frac{2}{3}:\frac{2}{3}\times x=1\)
\(1\times x=1\)
x = 1
b) \(x+x:5\times7,5+x:2\times9=315\)
\(x+x\cdot\frac{1}{5}\cdot7,5+x\cdot\frac{1}{2}\cdot9=315\)
\(x\cdot\left(1+\frac{1}{5}.7,5+\frac{1}{2}.9\right)=315\)
x.7 = 315
x = 45
Dấu . là dấu nhân nha
Tìm x :
a) 2/3 : 2/3 × X = 1
1 × X = 1
X = 1 : 1
X = 1
b) X + X : 5 × 7,5 + X : 2 × 9 = 315
X + X × 1/5 × 7,5 + X × 1/2 × 9 = 315
X × 1 + X × 1,5 + X × 4,5 = 315
X × ( 1 + 1,5 + 4,5 ) = 315
X × 7 = 315
X = 315 : 7
X = 45
VẬY X = 45
(-0.2)^2x5-(8^2x9^5)/3^9x4^3
\(=0.04\cdot5-\dfrac{2^6\cdot3^{10}}{3^9\cdot2^6}=0.2-3=-2.8\)
1) 1/1+2 + 1/1+2+3+.........+1/1+2+3+..............+10
2) 1+3+6+10+.........+45+55/1x10+2x9+.......+9x2+10x1
C = 3/1x2 + 3/2x3 + ... + 3/9x10 + 77/2x9
D = 2/1x2x3 + 2/3x4x5 + ...+2/99x100x101
E = 4/1x3x5 + 4/3x5x7 + ... + 4/9x11x13
(1+1/2+1/3+....+1/9+1/10)/ (1/1x10+1/2x9+1/3x8+....+1/8x3+1/9x2+1/10x1)
Tính nhanh